JP2020197897A - Virtual tape device, cache control device and cache control program - Google Patents

Abstract

To reduce the number of steps necessary for managing the token of a terminal manager, the archive thereof, and a password for the token, and to further improve the security level of a terminal device.SOLUTION: A virtual tape device includes: a cache memory that stores a plurality of logical volumes; a managing unit 10 that manages mount information 32 containing access time information for each of a plurality of logical volumes 210; and a selecting unit 20 that selects a to-be-cached-out logical volume 210 subjected to cache out from the cache memory among the plurality of logical volumes 210 stored in the cache memory. The selecting unit 20 preferentially selects, as the to-be-cached-out logical volume, the logical volume stored in a physical volume mounted on a physical drive most recently among the logical volumes to which a driven sequence is allocated.SELECTED DRAWING: Figure 3

Description

The present invention relates to a virtual tape device, a cache control device, and a cache control program.

The virtual tape device is a system for virtualizing a tape drive device and a cartridge tape. The virtual tape device is recognized as a tape device by the OS (Operating System) of the host computer connected to the virtual tape device. In the host computer, this virtualized tape (virtual tape) can be used in the same way as a normal tape device, so that the host computer can use the virtual tape device as if the real tape is mounted on it. Can be used as

The virtual tape device connects the backend library. The back-end library includes a tape drive device (physical drive), a plurality of tapes (physical volumes), and a transport mechanism for transporting the tape to the tape drive device.

Further, the virtual tape device includes a tape volume cache, and a virtual tape volume in which a tape (physical volume) is virtualized is stored in the tape volume cache.

In the virtual tape device, the data is stored in the virtual tape volume in the tape volume cache and then copied to the tape in the backend library, which double-manages the data.

In the virtual tape device, when the tape volume cache is full, it may be necessary to newly add a virtual tape volume to the tape volume cache. In such a case, after the old virtual tape volume in the tape volume cache is cached out from the tape volume cache, a new virtual tape volume is stored in this tape volume cache.

In the conventional virtual tape device, the virtual tape volume to be cached out from the tape volume cache is preferentially selected from the oldest data by the LRU (Least Recently Used) logic.

If you want to use the cached out virtual tape volume again, you need to perform a recall process to return the virtual tape volume to the tape volume cache from the backend library.

Such a recall process requires mechanical operations such as tape feeding and tape replacement in the tape drive device in the back-end library, which causes the host computer to wait for a long time to start the process.

In the conventional virtual tape device, in order to reduce the time required for such a recall process, for example, priority is given to the virtual tape volume in which the last update data exists in the physical volume (tape) mounted on the physical drive. Is subject to off-cache. As a result, when a recall request occurs, the probability that the data of the virtual tape volume to be recalled exists in the physical volume in use increases, and the recall time is shortened.

Japanese Unexamined Patent Publication No. 2013-161256

However, even in such a conventional virtual tape device, in order to determine a virtual tape volume in which the last updated data exists in the physical volume mounted on the physical drive, a machine such as tape feeding accompanying a search for the physical volume is performed. Action is required. That is, it is not possible to eliminate the waiting time of the host computer due to the mechanical operation for searching the physical volume.

In one aspect, the present invention aims to reduce response time to a host computer.

Therefore, this virtual tape device is a virtual tape device that manages a plurality of logical volumes created based on the data of the physical volumes mounted on the physical drive, and includes a cache memory for storing the plurality of logical volumes. , The management unit that manages the mount information including the access time information for each of the plurality of logical volumes, and the cash-out target logical volume to be cached out from the cache memory from the plurality of logical volumes stored in the cache memory. A selection unit is provided, and the selection unit preferentially selects a logical volume stored in the physical volume mounted on the physical drive as a cash-out target logical volume among the eviction-ordered logical volumes. ..

According to one embodiment, the response time to the host computer can be shortened.

It is a figure which shows typically the structure of the virtual tape system as an example of embodiment. It is a block diagram which shows the hardware structure of the VLP of the virtual tape apparatus as an example of an embodiment. It is a figure which shows the functional structure of the VLP of the virtual tape apparatus as an example of an embodiment. It is a figure which illustrates the LRU management table in the virtual tape apparatus as an example of an embodiment. It is a figure which illustrates the physical drive management table in the virtual tape apparatus as an example of an embodiment. It is a figure which illustrates the physical drive management table in the virtual tape apparatus as an example of an embodiment. It is a figure which illustrates the physical drive management table in the virtual tape apparatus as an example of an embodiment. It is a figure for demonstrating the position of a physical head with respect to a virtual volume on a physical volume. It is a figure for demonstrating the position of a physical head with respect to a virtual volume on a physical volume. It is a flowchart for demonstrating the selection method of the virtual volume to be cashed out in the virtual tape apparatus as an example of Embodiment. It is a flowchart for demonstrating the selection method of the virtual volume to be cashed out in the virtual tape apparatus as an example of Embodiment. It is a flowchart for demonstrating the selection method of the virtual volume to be cashed out in the virtual tape apparatus as an example of Embodiment.

Hereinafter, embodiments relating to the virtual tape device, the cache control device, and the cache control program will be described with reference to the drawings. However, the embodiments shown below are merely examples, and there is no intention of excluding the application of various modifications and techniques not specified in the embodiments. That is, the present embodiment can be implemented by various modifications (combining the embodiments and each modification) within a range that does not deviate from the purpose. In addition, each figure does not mean that it includes only the components shown in the figure, but may include other functions and the like.

(A) Configuration FIG. 1 is a diagram schematically showing a configuration of a virtual tape system as an example of an embodiment.
As shown in FIG. 1, the virtual tape system 1 includes a host device (upper device) 200, a virtual tape device 100, and a back-end library 300.

The host device 200 accesses the virtual tape (virtual volume, logical volume) 210 virtualized by the virtual tape device 100, and writes or reads the cartridge tape data of the back-end library 300. FIG. 1 shows an example in which the host device 200 is a mainframe host.

The host device 200 includes, for example, an ICP (Integrated Channel Processor) 150-0, 150-1, a tape volume cache 160, and an IDP (Integrated Device Processor) 170-0, 170- via an FC (Fibre Channel) switch (not shown). 1. It is communicably connected to the back-end library 300 (see the double line in FIG. 1). Further, the host device 200 may use a VLP (Virtual Library Processor) 110, a PLP (Physical Library Processor) 120, ICP150-0,150-1, IDP170-0,170-1 via a LANC (Local Area Network Controller) 131. , It is communicably connected to the back-end library 300 (see the alternate long and short dash line in FIG. 1).

The host device 200 issues an I / O processing request (read request / write request) to the virtual volume 210 or the cartridge tape (physical volume, physical tape). The host device 200 realizes, for example, an I / O processing request to a virtual volume by executing VTCP (Virtual Tape Control Program) by a CPU (Central Processing Unit) (not shown).

The host device 200 backs up data by, for example, transferring data stored in a storage device (not shown) and used for business or the like to a virtual volume 210 or a cartridge tape on a regular or irregular basis and copying the data.

The backup of this data is performed, for example, by designating a virtual volume 210 or a cartridge tape for storing the data.

The back-end library 300 writes and reads data on a cartridge tape (media, physical volume). The back-end library 300 includes one or more tape drives (physical drives), a storage shelf for storing a plurality of cartridge tapes, and a transport mechanism (robot; not shown) for transporting the cartridge tapes. The transport mechanism transports an arbitrary physical volume among a plurality of physical volumes stored in the transport shelf to the physical drive. The cartridge tape, the storage shelf, and the transport mechanism are not shown. Further, the configuration of the back-end library 300 can be realized by using various known methods, and the description thereof will be omitted for convenience.

Then, in the back-end library 300, the physical volume is moved in and out of the physical drive by the transport mechanism, and data is written / read to the physical volume loaded (mounted) on the physical drive.

The virtual tape device 100 emulates tape I / O (Input / Output).
The virtual tape device 100 intervenes between the host device 200 and the back-end library 300, and stores data transmitted and received between the host device 200 and the back-end library 300 as a virtual tape volume. Hereinafter, this virtual tape volume is referred to as a virtual volume, and is illustrated with reference numeral 210.

The virtual tape device 100 performs high-speed access to the disk based on the access from the host device 200 to the virtual volume 210.

The data of the virtual volume 210 of the tape volume cache 160 is collectively written on the cartridge tape (physical volume) of the backend library 300.

As shown in FIG. 1, the virtual tape device 100 includes VLP110, PLP120, ICP150-0,150-1, tape volume cache 160, IDP170-0,170-1, and LANC131.

The VLP 110 and PLP 120 are communicably connected to each other via the LANC 131. At least a part of ICP150-0,150-1, tape volume cache 160 and IDP170-0,170-1 may be communicably connected to these VLP110 and PLP120.

The host device 200 and the back-end library 300 are also connected to the LANC 131.

Further, ICP150-0,150-1, IDP170-0,170-1, VLP110, and tape volume cache 160 are connected to each other so as to be able to communicate with each other via an FC switch (not shown). Further, the host device 200 and the back-end library 300 are also connected to the FC switch. As a result, for example, between ICP150-0,150-1 and the tape volume cache 160, between the tape volume cache 160 and IDP170-0,170-1, IDP170-0,170-1 and the backend library 300 Data can be sent and received to and from each stored tape drive.

Then, in the virtual tape device 100, a plurality of processes communicate using pipes or sockets on each server of ICP150-0, 150-1, IDP170-0,170-1, and VLP110 to realize a virtual tape system. doing.

Further, these ICP150-0,150-1, tape volume cache 160, IDP170-0,170-1, VLP110, PLP120, LANC131 and backend library 300 are configured in the same rack (not shown). be able to.

The FC switch relays data and switches the route on the optical fiber channel communication path to which the ICP150-0 to 150-1, IDP170-0,170-1, VLP110 and the tape volume cache 160 are connected. In this optical fiber channel communication path, for example, data of a logical volume processed by the virtual tape device 100 is transmitted.

The LANC 131 relays data and switches the route on the LAN route to which the ICP150-0,150-1, IDP170-0,170-1, VLP110, PLP120 and the FC switch are connected. In this LAN path, for example, communication regarding operation status reference and operation instruction of each processing unit of ICP150-0,150-1 and IDP170-0,170-1 is performed. The LANC 131 distributes and connects the communication to all processing units.

The tape volume cache 160 is a storage medium (cache memory) in which a virtual tape volume (virtual volume, logical volume) which is virtual information of a cartridge tape is stored, and is an ICP 150-0, 150-1, IDP 170-0, It provides virtual storage for 170-1. The tape volume cache 160 functions as a virtual storage unit that stores data received by ICP150-0,150-1, which will be described later, and data read from the cartridge tape of the back-end library 300. A virtual volume (virtual tape volume) 210, which is a logical volume, is stored in the tape volume cache 160. The virtual volume indicates data in a logical access unit when data is accessed from the host device 200. The tape volume cache 160 is configured as, for example, a RAID (Redundant Arrays of Inexpensive Disks) device.

The actual data of the virtual volume 210 stored in the tape volume cache 160 is stored in the cartridge tape (physical volume) of the back-end library 300, which will be described later. Hereinafter, the actual data of the virtual volume 210 stored in the cartridge tape of the back-end library 300 may be referred to as a virtual volume on the physical volume or simply a virtual volume.

IDP170-0,170-1 is a server computer (processing unit) that controls the connection with the tape drive of the back-end library 300. In the virtual tape system 1, one or more IDPs 170-0 and 170-1 (two in the example shown in FIG. 1) are provided in the virtual tape device 100, and each controls the physical drive of the back-end library 300. These IDPs 170-0 and 170-1 have a similar configuration.

Hereinafter, as the code indicating the IDP, the code 170-0,170-1 is used when it is necessary to specify one of the plurality of IDPs, but the code 170 is used when referring to an arbitrary IDP.

The IDP 170 receives an instruction from the VLP 110 and writes the data of the logical volume on the tape volume cache 160 to the physical volume using the physical drive of the back-end library 300. Similarly, the IDP 170 receives an instruction from the VLP 110, reads the data of the logical volume from the physical volume using the physical drive of the back-end library 300, and stores it in the tape volume cache 160.

The IDP 170 reads data from the physical volume of the back-end library 300 and writes data in response to a data access request from the host device 200.

The IDP170 has a function as a PDS (Physical Driver Server). The PDS is a process of exchanging data with a cartridge tape inserted in the tape drive of the back-end library 300. For example, data is read from a physical volume, and the read data is read into a predetermined area of the tape volume cache 160. Write to. As a result, the IDP 170 realizes a function as a physical drive control unit that controls the physical drive of the back-end library 300.

ICP150-0,150-1 are server computers (processing units) that control the connection with the drive path of the host device 200. In the virtual tape system 1, one or more ICP150-0,150-1 (two in the example shown in FIG. 1) are provided in the virtual tape device 100, and as a receiving means for receiving data from the host device 200. Function. These ICPs 150-0 and 150-1 have a similar configuration. Hereinafter, as the code indicating ICP, reference numeral 150-0,150-1 is used when it is necessary to specify one of a plurality of ICPs, but reference numeral 150 is used when referring to an arbitrary ICP.

The ICP 150 is connected to the host device 200 via an FC switch, and controls transmission / reception of virtual tape volume data on the tape volume cache 160 to / from the host device 200. The ICP 150 accesses the data of the virtual tape volume of the tape volume cache 160 via the virtual drive (logical drive device) 151, and reads or writes the data. That is, the ICP 150 functions as a processing unit that controls data access to the virtual drive device.

This ICP150 is configured by, for example, an IA (Intel Architecture) server and realizes a function as an EMTAPE (Virtual Emulation Tape). EMTAPE is a process of virtually showing the tape drive of the back-end library 300 to the host device 200, and realizes the virtual drive 151. EMTAPE embodies the physical tape drive of the backend library 300. As a result, the ICP 150 realizes a function as a physical drive control unit that controls the virtual drive 151. The virtual drive 151 may be called a logical drive. FIG. 1 shows an example in which the virtual tape device 100 is provided with five virtual drives 151.

Hereinafter, as the code indicating ICP, reference numeral 150-0,150-1 is used when it is necessary to specify one of a plurality of ICPs, but reference numeral 150 is used when referring to an arbitrary ICP.

The PLP 120 is a server computer (processing unit) that controls the operation of the back-end library 300. The PLP 120 controls the transfer mechanism of the back-end library 300 in accordance with the control request of the back-end library 300 received from the VLP 110, which will be described later, so that the physical drive (not shown) is loaded with the cartridge tape (physical volume) or the physical. Remove the physical volume from the drive.

The VLP110 is a server computer (processing unit) that executes (operates) various processes for realizing a virtual tape environment as a system in cooperation with ICP150-0,150-1 and IDP170-0,170-1. .. The VLP 110 receives a mount request from the host device 200 via LANC 131, mounts a logical volume on the virtual drive 151, and performs mount processing and unmount processing of the physical volume of the tape drive.

The VLP 110 is connected to the host device 200 via the LANC 131, and receives a data writing request from the host device 200 and the like. Then, the VLP 110 requests the PLP 120, the ICP server 150, and the IDP 170 to read / write data and control the back-end library 300.

The VLP 110 controls data access to the tape volume cache 160. The VLP 110 is a cache control device that controls a cache memory (tape volume cache 160) that stores a plurality of logical volumes (virtual volumes 210) created based on the data of the physical volumes mounted on the physical drive of the back-end library 300. Corresponds to.

FIG. 2 is a block diagram showing the hardware configuration of the VLP 110 of the virtual tape device 100 as an example of the embodiment, and FIG. 3 is a diagram showing the functional configuration thereof.

As illustrated in FIG. 2, the VLP 110 includes a processor 11, a memory 12, a storage device 13, a graphic processing device 14, an input interface 15, an optical drive device 16, a device connection interface 17, and a network interface 18 as components. These components 11 to 18 are configured to be communicable with each other via the bus 19.

The processor (processing unit) 11 controls the entire VLP110. The processor 11 may be a multiprocessor. The processor 11 is, for example, any one of a CPU, an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), and an FPGA (Field Programmable Gate Array). You may. Further, the processor 11 may be a combination of two or more types of elements of the CPU, MPU, DSP, ASIC, PLD, and FPGA.

Then, when the processor 11 executes a control program for the VLP 110 (cache control program; not shown), the virtual volume management unit 10, the virtual volume selection unit 20, and the virtual volume deletion unit 40, which will be described later with reference to FIG. The function of is realized.

The functions of the virtual volume management unit 10, the virtual volume selection unit 20, and the virtual volume deletion unit 40 may be implemented as, for example, functions that operate on an OS (Operating System) program, or as functions of an OS program. May be done.

The VLP 110 executes a program (cache control program or OS program) recorded on a computer-readable non-temporary recording medium, for example, to execute the virtual volume management unit 10 and the virtual volume selection unit 20 shown in FIG. And the function as the virtual volume deletion unit 40 is realized.

The program that describes the processing content to be executed by the VLP110 can be recorded on various recording media. For example, a cache control program to be executed by the VLP 110 can be stored in the storage device 13. The processor 11 loads at least a part of the program in the storage device 13 into the memory (RAM) 12 and executes the loaded program.

Further, the program (cache control program) to be executed by the VLP 110 (processor 11) can be recorded on a non-temporary portable recording medium such as an optical disk 16a, a memory device 17a, and a memory card 17c. The program stored in the portable recording medium can be executed after being installed in the storage device 13 under the control of, for example, the processor 11. The processor 11 can also read and execute the program directly from the portable recording medium.

The memory 12 is a storage memory including a ROM (Read Only Memory) and a RAM (Random Access Memory). The RAM of the memory 12 is used as the main storage device of the VLP 110. At least a part of the OS program and the control program (cache control program) to be executed by the processor 11 is temporarily stored in the RAM. Further, various data necessary for processing by the processor 11 are stored in the memory 12.

The storage device 13 is a storage device such as a hard disk drive (HDD), SSD (Solid State Drive), and storage class memory (SCM), and stores various types of data. The storage device 13 is used as an auxiliary storage device for the VLP 110. The storage device 13 stores an OS program, a control program, and various data. The control program includes monitoring software.

As the auxiliary storage device, a semiconductor storage device such as an SCM or a flash memory can also be used. In addition, RAID (Redundant Arrays of Inexpensive Disks) may be configured by using a plurality of storage devices 13.

Further, the storage device 13 stores data constituting the LRU management table 31 and the physical drive management table 32, which will be described later.

A monitor 14a is connected to the graphic processing device 14. The graphic processing device 14 causes the image to be displayed on the screen of the monitor 14a in accordance with the instruction from the processor 11. Examples of the monitor 14a include a display device using a CRT (Cathode Ray Tube), a liquid crystal display device, and the like.

A keyboard 15a and a mouse 15b are connected to the input interface 15. The input interface 15 transmits signals sent from the keyboard 15a and the mouse 15b to the processor 11. The mouse 15b is an example of a pointing device, and other pointing devices can also be used. Examples of other pointing devices include touch panels, tablets, touch pads, trackballs, and the like.

The optical drive device 16 reads the data recorded on the optical disk 16a by using a laser beam or the like. The optical disc 16a is a portable non-temporary recording medium on which data is readablely recorded by reflection of light. Examples of the optical disk 16a include a DVD (Digital Versatile Disc), a DVD-RAM, a CD-ROM (Compact Disc Read Only Memory), a CD-R (Recordable) / RW (ReWritable), and the like.

The device connection interface 17 is a communication interface for connecting peripheral devices to the VLP 110. For example, a memory device 17a or a memory reader / writer 17b can be connected to the device connection interface 17. The memory device 17a is a non-temporary recording medium equipped with a communication function with the device connection interface 17, for example, a USB (Universal Serial Bus) memory. The memory reader / writer 17b writes data to the memory card 17c or reads data from the memory card 17c. The memory card 17c is a card-type non-temporary recording medium.

The network interface 18 is connected to the network. The network interface 18 may include an interface (FC interface) connected to the optical fiber channel network and a LAN interface connected to the LAN. The VLP 110 transmits / receives data to / from the PLP 120, the host device 200, the tape volume cache 160, the ICP 150, the IDP 170, and the like via the network interface 18. Other information processing devices, communication devices, and the like may be connected to the network.

Next, the functional configuration of the VLP110 will be described. As shown in FIG. 3, the VLP 110 has functions as a virtual volume management unit 10, a virtual volume selection unit 20, and a virtual volume deletion unit 40.

The virtual volume management unit 10 manages the virtual volume 210 in the virtual tape device 100. The virtual volume management unit 10 manages the virtual volume 210 by using the LRU management table 31 and the physical drive management table 32.

FIG. 4 is a diagram illustrating an LRU management table 31 in the virtual tape device 100 as an example of the embodiment.

The LRU management table 31 is virtual volume management information for managing the virtual volume 210, and ranks and manages the virtual volume 210 to which data has been accessed according to the LRU logic. That is, the LRU management table 31 is configured by arranging the virtual volumes 210 according to the elapsed time from the time when the last access was performed.

The LRU management table 31 illustrated in FIG. 4 is configured as a table including the virtual volume name, the presence / absence of the virtual volume mount, the volume to be stored, the size, and the time stamp of the last access to the virtual volume as columns.

The virtual volume name is identification information that identifies the virtual volume 210. The size is the data size of the virtual volume 210. The time stamp of the last access to the virtual volume indicates the time when the last data access was made to the virtual volume 210. In the LRU management table 31, the virtual volume 210 having the oldest time stamp of the last access to this virtual volume is sorted so as to be the head (the highest position in FIG. 4).

The presence / absence of the virtual volume mount is information indicating whether or not the cartridge tape (physical volume) for storing the actual data corresponding to the virtual volume 210 is mounted on the physical drive of the back-end library 300. When the virtual volume 210 is stored in the physical volume mounted on the physical drive of the back-end library 300, for example, "1" is set for whether or not the virtual volume is mounted. On the other hand, when the virtual volume 210 is not stored in the physical volume mounted on the physical drive of the back-end library 300, for example, "0" is set for whether or not the virtual volume is mounted.

The volume to be stored is identification information that identifies a cartridge tape (physical volume) that stores actual data corresponding to the virtual volume 210.

Therefore, in the LRU management table 31, the virtual volume 210 in which “1” is set for the presence / absence of the virtual volume mount has the corresponding actual data stored in the cartridge tape specified by the physical volume to be stored. The actual data corresponding to the virtual volume 210 includes data for realizing the virtual volume 210.

The virtual volume management unit 10 records and updates information in the LRU management table 31.

Further, the virtual volume management unit 10 manages the cartridge tape (physical volume) mounted on the physical drive of the back-end library 300 and the virtual volume stored in the physical volume by using the physical drive management table 32. To do.

5 to 7 are diagrams illustrating the physical drive management table 32 in the virtual tape device 100 as an example of the embodiment, and one physical drive management table 32 is divided and shown in FIGS. 5 to 7. There is.

The physical drive management table 32 illustrated in FIGS. 5 to 7 shows the physical drive No., whether or not the physical volume is mounted, the time stamp of the mounted time, the physical volume, the time stamp of the last access to the physical volume, the position of the head, and the virtual. It is configured as a table with the number of volumes, virtual volume number, virtual volume name, and capacity as columns.

In the figure, the same column name as the described column name has the same contents, so the description thereof will be omitted.

The physical drive number is identification information that identifies the physical drive. The presence / absence of physical volume mounting is information indicating whether or not a cartridge tape (physical volume) is mounted on the physical drive. When a physical volume is mounted on the physical drive, for example, "1" is set for whether or not the physical volume is mounted. On the other hand, when the physical volume is not mounted on the physical drive, for example, "0" is set for whether or not the physical volume is mounted.

The mounted time time stamp indicates the time when the physical volume was mounted when the physical volume was mounted on the physical drive.

The physical volume is identification information that identifies the physical volume mounted on the physical drive. The time stamp of the last access to the physical volume indicates the time when the last data access was made to the physical volume mounted on the physical drive.

The position of the head indicates the position of the head (physical head, magnetic head) of the physical drive with respect to the physical volume mounted on the physical drive.

In the virtual tape device 100, it is assumed that the data of the virtual volume 210 is sequentially stored in the physical volume. Hereinafter, for convenience, the data of the virtual volume 210 in the physical volume may be simply referred to as the virtual volume in the physical volume.

In the example shown in FIG. 6, the position of the Head is represented by the position of the physical volume with respect to the virtual volume. That is, Head by combining the code "VV No.n" (n is a natural number) representing the virtual volume No. and "after" indicating that the physical head of the physical drive is at the end position of the data of the virtual volume 210. Indicates the position of.

For example, in the physical volume, the end position of the data of the virtual volume 210 whose virtual volume No. is “1” is represented as “after VV No. 1”. That is, the position of the Head is represented by using the virtual volume No. of the virtual volume in the physical volume.

The method of expressing the position of the Head is not limited to this, and can be appropriately modified and implemented. For example, when the physical head of the physical drive is at the head position of the data of the virtual volume 210 on the physical volume, it may be expressed as "VV No. n before".

Further, the position of the Head may be expressed by using the length and coordinates from the beginning of the cartridge tape, or a value similar thereto.

The number of virtual volumes is the number of virtual volumes stored in the physical volume mounted on the physical drive.

The virtual volume No. is an identification number for identifying the virtual volume stored in the physical volume mounted on the physical drive.

When the data of a plurality of virtual volumes 210 is stored in the physical volume, the virtual volume numbers and virtual volumes of the plurality of virtual volumes are associated with the physical volume in the physical drive management table 32. The volume name and capacity are recorded.

The virtual volume management unit 10 also records and updates information in the physical drive management table 32. The virtual volume management unit 10 may acquire the information to be recorded in the physical drive management table 32 by referring to the directory information (configuration information) recorded in the cartridge tape, for example.

When the tape volume cache 160 is full, the virtual volume selection unit 20 expels the tape volume cache 160 from the tape volume cache 160 in order to make free space for storing a new virtual volume in the tape volume cache 160 (cache out). ) Select the virtual volume 210. That is, the virtual volume selection unit 20 selects the virtual volume 210 to be cached out in the tape volume cache 160.

The virtual volume selection unit 20 can cache out all the virtual volumes 210 whose corresponding physical volumes are mounted on the physical drive in the back-end library 300 among the virtual volumes 210 stored in the tape volume cache 160. Select as.

When there are a plurality of virtual volume candidates to be cached out in the tape volume cache 160 and there are a plurality of physical volumes for storing these virtual volumes 210 in the back-end library 300, the virtual volume selection unit 20 finally assesses. Selects the physical volume with the latest time when was performed.

That is, the virtual volume selection unit 20 refers to the physical drive management table 32, compares the value of the time stamp last accessed to the physical volume, and selects the physical volume having the latest time stamp value (time).

Then, the virtual volume selection unit 20 selects the virtual volume 210 in which the actual data is stored in the selected physical volume as a candidate for the cash-out target.

The virtual volume selection unit 20 refers to a plurality of virtual volumes 210 registered in the LRU management table 31 that have been banished and ranked, and among the virtual volumes 210, the virtual volume that is stored in the physical volume most recently mounted on the physical drive. The volume 210 is preferentially selected as the virtual volume to be cashed out (logical volume 210 to be cashed out).

A virtual tape system is known to have a function of forcibly unmounting a physical volume mounted on a physical drive when the physical volume has not been accessed for a predetermined period of time. In a virtual tape system having such a function, a physically unmounted physical volume is forcibly selected from the physical drive. Thereby, for example, when the cached out virtual volume 210 is recalled and reused, the restoration of the virtual volume from the physical volume can be realized in a shorter time.

The physical volume with the latest value (time) of the time stamp that last accessed the physical volume is the physical volume that has recently been accessed for data, and it is considered that there is a high probability that data access will occur.

Further, the virtual volume selection unit 20 selects the virtual volume 210 in which "1" (yes) is set for the presence / absence of the virtual volume mount in the LRU management table 31 as a candidate for the cash out target.

That is, the virtual volume selection unit 20 selects the virtual volume 210 in which the actual data is stored in the physical volume mounted on the physical drive of the back-end library 300 as a candidate for the cash-out target.

Further, when the virtual volume selection unit 20 has a plurality of virtual volumes 210 that are candidates for cash-out and their actual data is stored in the same physical volume, the position of the physical head of the physical drive in this physical volume. Select the virtual volume closest to is the cashout target.

The virtual volume selection unit 20 specifies the position of each virtual volume on the physical volume, calculates the distance to the position on the physical volume where the virtual volume is stored with respect to the position of the physical head of the physical drive, and the position of the physical head. Select the virtual volume closest to. That is, the virtual volume selection unit 20 selects a virtual volume 210 whose actual data is at a position accessible by a small amount of movement (movement time) of the physical head in the physical volume as a cache-out target.

8 and 9, respectively, are diagrams for explaining the position of the physical head with respect to the virtual volume on the physical volume.

In the example shown in FIG. 8, a state in which a plurality of virtual volumes (VV-1 to VV-6) are stored on the physical volume is shown. In the figure, the left side is the beginning side of the physical volume, and the right side is the end side of the physical volume. Therefore, in the physical volume, the virtual volume VV-1 is first, followed by the virtual volume VV-1, and the virtual volumes VV-2 to VV-6 are stored in order. Further, the physical head of the physical drive is located at the end position of the virtual volume VV-3.

Further, in the example shown in FIG. 8, the capacities of the virtual volumes VV-1 and VV-2 are 100MB and 200MB, and the capacities of the virtual volumes VV-3 to VV-6 are 300MB.

In the state illustrated in FIG. 8, when 900 MB of free space is required for the tape volume cache 160, the virtual volumes VV-4 to VV that are continuous with the virtual volume VV-4 that minimizes the movement of the physical head are the first. It is desirable to select -6 as the cash-out target. As a result, the data of the virtual volume 210 to be cashed out can be quickly written to the physical volume, and the time required for cashing out can be shortened.

In the example shown in FIG. 9, a state in which a plurality of virtual volumes (VV-1 to VV-7) are stored on the physical volume is shown. In the figure, the left side is the beginning side of the physical volume, and the right side is the end side of the physical volume. Therefore, in the physical volume, the virtual volume VV-1 is first, followed by the virtual volume VV-1, and the virtual volumes VV-2 to VV-7 are stored in order. Also, the physical head of the physical drive is at the end of the virtual volume VV-4.

In the example shown in FIG. 9, the capacities of the virtual volumes VV-1, VV-2, and VV-4 are 100MB, 200MB, and 900MB, and the capacities of the virtual volumes VV-3, VV-5 to VV-7. Is 300MB.

In the state illustrated in FIG. 9, when 900 MB of free space is required for the tape volume cache 160, the virtual volumes VV-5 to VV-7 that are continuous with the virtual volume VV-5 at the beginning are set as cache-out targets. It is conceivable to select (Plan A). It is also conceivable to select VV-4 having a capacity of 900 MB as a cash-out target (Proposal B).

However, in Plan B, a mechanical operation (rewinding of the physical volume) for moving the physical head to the beginning of the virtual volume VV-4 occurs, so Plan A that does not involve such mechanical operation is adopted. It is desirable to do.

That is, it is desirable that the virtual volume selection unit 20 preferentially determines the virtual volume 210 in which the actual data is stored at a position downstream (tailward) of the physical head on the physical volume.

As a result, the data of the virtual volume 210 to be cashed out can be quickly written to the physical volume, and the time required for cashing out can be shortened.

Further, when selecting the virtual volume 210 to be cashed out, the virtual volume selection unit 20 may consider the time required for rewinding the physical volume for positioning the physical head. Virtual data is stored at a position upstream of the physical head (head direction) compared to data access to the virtual volume 210 where the actual data is stored at a position downstream (end direction) from the physical head. If the data can be accessed to the volume 210 in a short time, the virtual volume 210 in which the actual data is stored at the upstream position may be the cash-out target.

As a result, the data of the virtual volume 210 to be cashed out can be quickly written to the physical volume, and the time required for cashing out can be shortened.

When the physical volume is not mounted on the physical drive of the back-end library 300, the virtual volume selection unit 20 is a cache-out target from the plurality of virtual volumes 210 stored in the tape volume cache 160 according to the LRU logic. Virtual volume 210 is selected.

That is, the virtual volume selection unit 20 refers to the LRU management table 31 and selects the virtual volume 210 having the oldest time stamp that last accessed the virtual volume as the cash-out target. The virtual volume selection unit 20 selects the virtual volume 210 entered at the top (top position in the figure) of the LRU management table 31 illustrated in FIG. 4 as a cash-out target.

The virtual volume selection unit 20 notifies the virtual volume deletion unit 40 of the virtual volume 210 selected as the cash-out target.

Further, the virtual volume selection unit 20 confirms whether the free space required for the tape volume cache 160 is secured after deleting the virtual volume 210 selected as the cache-out target. As a result of the confirmation, if the free space required for the tape volume cache 160 is not secured, the virtual volume 210 to be cached out is selected and the virtual volume deletion unit 40 is notified again.

The virtual volume deletion unit 40 deletes the virtual volume 210 selected as the cache-out target by the virtual volume selection unit 20 from the tape volume cache 160.

The deletion of the virtual volume 210 from the tape volume cache 160 can be realized by a known method, and detailed description thereof will be omitted. For example, the virtual volume deletion unit 40 caches the virtual volume 210 by deleting the entry of the virtual volume 210 to be cached out from the management table (not shown) that manages the virtual volume 210 stored in the tape volume cache 160. Achieve out.

(B) Operation The flowcharts (steps A1 to A17, B1 to 2) shown in FIGS. 10 to 12 show a method of selecting a virtual volume 210 to be cashed out in the virtual tape device 100 as an example of the embodiment configured as described above. This will be described according to B2). Note that FIG. 10 shows the processing of steps A1 to A6, and FIG. 11 shows the processing of steps A7 to A17. Further, FIG. 12 shows the processing of steps B1 to B2.

In the following processing, the variable "total virtual volume capacity to be cashed out" is used.

In step A1, the virtual volume selection unit 20 initializes the variable “total virtual volume capacity to be cashed out” and sets it to 0.

In step A2, the virtual volume selection unit 20 confirms the number of physical volumes (cartridge tapes) mounted on the physical drive, and determines whether the number of physical volumes mounted on the physical drive is 0.

As a result of the confirmation, if the number of physical volumes mounted on the physical drive is 0 (see the YES route in step A2), that is, if the physical volumes are not mounted on the physical drive, the process proceeds to step A14. ..

In step A14, the virtual volume selection unit 20 selects the virtual volume 210 to be cached out from the plurality of virtual volumes 210 stored in the tape volume cache 160 according to the LRU logic.

That is, the virtual volume selection unit 20 selects the virtual volume 210 having the oldest time stamp that last accessed the virtual volume as the cash-out target. Specifically, the virtual volume selection unit 20 refers to the LRU management table 31 and selects the virtual volume 210 entered at the top of the LRU management table 31 (upper position: the highest position in the figure) as a cashout target. To do.

In step A15, the virtual volume selection unit 20 refers to the LRU management table 31 and acquires the size of the virtual volume 210 to be cashed out selected in step A14. The virtual volume selection unit 20 adds the size of the acquired virtual volume 210 to the variable “total of virtual volume capacities to be cashed out”.

In step A16, the virtual volume deletion unit 40 deletes the cache-out target virtual volume 210 selected in step A14 from the tape volume cache 160. Further, the virtual volume deletion unit 40 deletes the registration of the virtual volume 210 to be cashed out from the LRU management table 31. That is, the LRU management table 31 is updated.

In step A17, the virtual volume selection unit 20 compares the value of the variable “total virtual volume capacity to be cached out” with the capacity required in the tape volume cache 160, and is greater than or equal to the required capacity. Check if there is.

As a result of the confirmation, when the variable "total of virtual volume capacities to be cached out" is equal to or greater than the capacity required in the tape volume cache 160 (see YES route in step A17), the process ends.

On the other hand, as a result of the confirmation in step A17, if the variable “total virtual volume capacity to be cached out” is less than the capacity required in the tape volume cache 160 (see NO route in step A17), the process returns to step A14. ..

Also, as a result of the confirmation in step A2, when the number of physical volumes mounted on the physical drive is not 0 (see the NO route in step A2), that is, when one or more physical volumes are mounted on the physical drive. To step A3.

In step A3, the virtual volume selection unit 20 refers to the LRU management table 31 and selects all the virtual volumes 210 for which “1 (yes)” is set for the presence / absence of the virtual volume mount as cash-out target candidates.

In step A4, the virtual volume selection unit 20 refers to the LRU management table 31, and sets “0 (none)” for the presence / absence of virtual volume mount for all of the virtual volumes 210 of the cashout target candidates selected in step A3. Check if it is done.

If "0 (none)" is set for the presence / absence of virtual volume mounting in all of the selected virtual volumes 210 that are candidates for cash out (see the YES route in step A4), for example, the physical volume is in the physical drive. This is a case where the physical volume is mounted but has nothing to do with the virtual volume 210. In such a case, the process proceeds to step A14.

On the other hand, as a result of the confirmation in step A4, when "1 (Yes)" is set for the presence / absence of the virtual volume mount in at least a part of the selected virtual volume 210 of the cashout target candidate (NO route in step A4). (See), and the process proceeds to step A5.

In step A5, the virtual volume selection unit 20 refers to the LRU management table 31 and counts the number of physical volumes that store the actual data of the virtual volume 210 of the cashout target candidate selected in step A3.

In step A6, the virtual volume selection unit 20 confirms whether the number of physical volumes counted in step A5 is plural. As a result of the confirmation, when the number of physical volumes for storing the actual data of the virtual volume 210 of the cash-out target candidate is multiple, that is, the virtual volume 210 of the cash-out target candidate is stored over the plurality of physical volumes. In the case (see the YES route in step A6), the process proceeds to step A7.

In step A7, the virtual volume selection unit 20 refers to the physical drive management table 32 and selects the physical volume having the latest time stamp of the last access to the physical volume.

In step A8, the virtual volume selection unit 20 is a virtual volume stored in the physical volume selected in step A7 with reference to the physical drive management table 32, and the presence / absence of the virtual volume mount is “1 (yes)). The virtual volume 210 that is "" is selected as a cashout target candidate.

In step A9, the virtual volume selection unit 20 confirms whether or not there are a plurality of virtual volumes 210 of the cashout target candidates selected in step A8. If there are a plurality of virtual volumes 210 that are candidates for cash out (see the YES route in step A9), the process proceeds to step A10.

In step A10, the virtual volume selection unit 20 uses the virtual volume 210 in which the actual data is stored in the physical volume mounted on the physical drive, and the storage position of the actual data in the physical volume is closest to the position of the physical head. Select 210.

The details of the process of step A10 will be described with reference to the flowchart shown in FIG. In the flowchart shown in FIG. 12, the input value is the virtual volume 210 of the cashout target candidate selected in step A8.

In step B1, the virtual volume selection unit 20 sets the position of the physical head and the actual data of each virtual volume 210 on the physical volume in the physical drive on which the physical volume for storing the actual data of the virtual volume 210 that is a candidate for cash out target is mounted. Calculate the distance to each data position.

In step B2, the virtual volume selection unit 20 determines the virtual volume 210 having the shortest distance between the calculated physical head position and the actual data position of each virtual volume 210 on the physical volume as the virtual volume 210 to be cashed out. To do. After that, the process proceeds to step A11 of FIG.

In step A11, the virtual volume selection unit 20 refers to the LRU management table 31 and acquires the size of the virtual volume 210 to be cashed out selected in step A10. The virtual volume selection unit 20 adds the size of the acquired virtual volume 210 to the variable “total of virtual volume capacities to be cashed out”. Further, as a result of the confirmation in step A9, even if there are no plurality of virtual volumes 210 as candidates for cash out (see the NO route in step A9), the process proceeds to step A11.

In step A12, the virtual volume deletion unit 40 deletes the cache-out target virtual volume 210 selected in step A10 from the tape volume cache 160. Further, the virtual volume deletion unit 40 deletes the registration of the virtual volume 210 to be cashed out from the LRU management table 31. That is, the LRU management table 31 is updated.

In step A13, the virtual volume selection unit 20 compares the value of the variable “total virtual volume capacity to be cached out” with the capacity required in the tape volume cache 160, and is greater than or equal to the required capacity. Check if there is.

As a result of the confirmation, when the variable "total of the virtual volume capacities to be cached out" is equal to or larger than the capacity required in the tape volume cache 160 (see the YES route in step A13), the process ends.

On the other hand, as a result of confirmation, if the variable "total of virtual volume capacities to be cached out" is less than the capacity required in the tape volume cache 160 (see NO route in step A13), the process returns to step A3.

(C) Effect As described above, according to the virtual tape system 1 as an embodiment of the present invention, the virtual volume selection unit is used to secure free space for adding a new virtual volume 210 to the tape volume cache 160. 20 preferentially selects the virtual volume 210 stored in the physical volume most recently mounted on the physical drive as the cache-out target among the virtual volumes 210 that have been expelled and ranked in the LRU management table 31. Therefore, there is a high probability that the virtual volume stored in the physical volume mounted on the physical drive will be selected.

As a result, in order to reuse the cached-out virtual volume, it is possible to increase the possibility that the recall process of returning the virtual volume from the back-end library 300 to the tape volume cache 160 can be realized in a short time. That is, the response time to the host device 200 can be shortened.

When there are a plurality of virtual volume candidates to be cashed out and there are a plurality of physical volumes for storing those virtual volumes, the virtual volume selection unit 20 selects the virtual volume to be stored in the last accessed physical volume. .. This allows the physical volume that stores the virtual volume to be used to be mounted on the physical drive for a longer time than other physical volumes, so that the mounted physical volume is mounted when the cached out virtual volume is reused. There are many opportunities to recall the virtual volume from the user, and as a result, the recall process of the virtual volume to the tape volume cache 160 can be performed in a short time. This also makes it possible to shorten the response time to the host device 200.

Further, when the virtual volume selection unit 20 stores the actual data of a plurality of candidate virtual volumes to be cached out in the same physical volume, the actual data is stored at a position close to the physical head in the physical drive. Priority is given to the virtual volume that is selected.

As a result, when the cashed-out virtual volume is used again, the head can be positioned in the virtual volume in the shortest time. Therefore, the recall process of the virtual volume to the tape volume cache 160 can be performed in a shorter time than recalling the virtual volume from the physical volume that is not mounted on the physical drive. This also makes it possible to shorten the response time to the host device 200.

(D) Others The disclosed technology is not limited to the above-described embodiment, and can be variously modified and implemented without departing from the spirit of the present embodiment. Each configuration and each process of the present embodiment can be selected as necessary, or may be combined as appropriate.

For example, in the virtual tape device 100, the number of ICP 150s and IDP 170s mounted is not limited to two, and various modifications can be made.

Further, the LRU management table 31 and the physical drive management table 32 are not limited to the table-shaped data structure, and can be modified in various ways.

Further, according to the above-mentioned disclosure, it is possible for a person skilled in the art to carry out and manufacture this embodiment.

(E) Additional notes The following additional notes will be further disclosed with respect to the above embodiments.

(Appendix 1)
A virtual tape device that manages multiple logical volumes created based on the data of a physical volume mounted on a physical drive.
A cache memory for storing the plurality of logical volumes and
A management unit that manages mount information including access time information for each of the plurality of logical volumes, and a management unit.
A selection unit for selecting a cache-out target logical volume to be cached out from the cache memory from the plurality of logical volumes stored in the cache memory is provided.
The selection part
A virtual tape characterized in that, among the eviction-ordered logical volumes, the logical volume stored in the physical volume most recently mounted on the physical drive is preferentially selected as the cash-out target logical volume. apparatus.

(Appendix 2)
The selection part
The virtual tape device according to Appendix 1, wherein the cash-out target logical volume is selected according to the eviction order when there is no logical volume stored in the physical volume mounted on the physical drive most recently.

(Appendix 3)
The selection part
When there are a plurality of the logical volumes stored in the physical volume mounted on the physical drive, the logical volume in which the distance between the storage position on the physical volume and the position of the physical head of the physical drive is short is described. The virtual tape device according to Appendix 1, wherein the logical volume to be cashed out is preferentially selected.

(Appendix 4)
A cache control device that controls a cache memory that stores multiple logical volumes created based on the data of a physical volume mounted on a physical drive.
A management unit that manages mount information including access time information for each of the plurality of logical volumes, and a management unit.
A selection unit for selecting a cache-out target logical volume to be cached out from the cache memory from the plurality of logical volumes stored in the cache memory is provided.
The selection part
Among the eviction-ordered logical volumes, the logical volume stored in the physical volume most recently mounted on the physical drive is preferentially selected as the cash-out target logical volume. apparatus.

(Appendix 5)
The selection part
The cache control device according to Appendix 4, wherein when there is no logical volume stored in the physical volume mounted on the physical drive most recently, the cache-out target logical volume is selected according to the eviction order.

(Appendix 6)
The selection part
When there are a plurality of the logical volumes stored in the physical volume mounted on the physical drive, the logical volume in which the distance between the storage position on the physical volume and the position of the physical head of the physical drive is short is described. The cache control device according to Appendix 4, wherein the logical volume to be cashed out is preferentially selected.

(Appendix 7)
To the processor of the cache control device that controls the cache memory that stores multiple logical volumes created based on the data of the physical volume mounted on the physical drive.
It manages mount information including access time information for each of the plurality of logical volumes.
From the plurality of logical volumes stored in the cache memory, a cache-out target logical volume to be cached out from the cache memory is selected.
A cache control program that executes a process of preferentially selecting a logical volume stored in a physical volume mounted on the physical drive as the cash-out target logical volume among the eviction-ordered logical volumes. ..

(Appendix 8)
The cache according to Appendix 7, which causes the processor to execute a process of selecting the cache-out target logical volume according to the eviction order when there is no logical volume stored in the physical volume mounted on the physical drive most recently. Control program.

(Appendix 9)
When there are a plurality of the logical volumes stored in the physical volume mounted on the physical drive, the logical volume in which the distance between the storage position on the physical volume and the position of the physical head of the physical drive is short is described. The cache control program according to Appendix 7, which causes the processor to execute a process of preferentially selecting a logical volume to be cached out.
The cache control device according to Appendix 4, wherein the cache control device is characterized in that.

1 Virtual tape system 10 Virtual volume management unit 20 Virtual volume selection unit 30 Storage unit 40 Virtual volume deletion unit 31 LRU management table 32 Physical drive management table 100 Virtual tape device 110 VLP
120 PLP
131 LANC
150-0,150-1,150 ICP
160 Tape Volume Cache 170-0,170-1,170 IDP
200 Host device 210 Virtual volume 300 Backend library

Claims (5)

A virtual tape device that manages multiple logical volumes created based on the data of a physical volume mounted on a physical drive.
A cache memory for storing the plurality of logical volumes and
A management unit that manages mount information including access time information for each of the plurality of logical volumes, and a management unit.
A selection unit for selecting a cache-out target logical volume to be cached out from the cache memory from the plurality of logical volumes stored in the cache memory is provided.
The selection part
A virtual tape characterized in that, among the eviction-ordered logical volumes, the logical volume stored in the physical volume most recently mounted on the physical drive is preferentially selected as the cash-out target logical volume. apparatus. The selection part
The virtual tape device according to claim 1, wherein when there is no logical volume stored in the physical volume mounted on the physical drive most recently, the cash-out target logical volume is selected according to the eviction order. .. The selection part
When there are a plurality of the logical volumes stored in the physical volume mounted on the physical drive, the logical volume in which the distance between the storage position on the physical volume and the position of the physical head of the physical drive is short is described. The virtual tape device according to claim 1, wherein the virtual tape device is preferentially selected as a cash-out target logical volume. A cache control device that controls a cache memory that stores multiple logical volumes created based on the data of a physical volume mounted on a physical drive.
A management unit that manages mount information including access time information for each of the plurality of logical volumes, and a management unit.
A selection unit for selecting a cache-out target logical volume to be cached out from the cache memory from the plurality of logical volumes stored in the cache memory is provided.
The selection part
Among the eviction-ordered logical volumes, the logical volume stored in the physical volume most recently mounted on the physical drive is preferentially selected as the cash-out target logical volume. apparatus. To the processor of the cache control device that controls the cache memory that stores multiple logical volumes created based on the data of the physical volume mounted on the physical drive.
It manages mount information including access time information for each of the plurality of logical volumes.
From the plurality of logical volumes stored in the cache memory, a cache-out target logical volume to be cached out from the cache memory is selected.
A cache control program that executes a process of preferentially selecting a logical volume stored in a physical volume mounted on the physical drive as the cash-out target logical volume among the eviction-ordered logical volumes. ..

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