JPH11184753A - Hierarchy storage system and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hierarchy storage system in which both high speed and high reliability can be established by using write back control and write through control by units. SOLUTION: At the time of receiving a write request from a host system, a host communication control part 11 judges whether a unit being the object of write uses a cache storage (cache memory 21, cache disk device 22), or not directly operates write to a magneto-optical disk stored in a magneto-optical disk autochanger 23 by referring to a unit management table 14, and communicates the judged result to a hierarchy storage controlling part 12. Then, when the cache storage is not used, the hierarchy storage controlling part 12 outputs a write instruction to directly transfer data to the magneto- optical disk autochanger 23 to a data flow controlling part 13. On the other hand, when the cache storage is used, the hierarchy storage controlling part 12 outputs a write instruction to transfer data to the cache storage device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a hierarchical storage system for constructing a high-speed and large-capacity storage device by combining, for example, a semiconductor memory, a magnetic disk device, and a magneto-optical disk autochanger in multiple stages. More particularly, the present invention relates to a hierarchical storage system and a hierarchical storage control method that achieve both high speed and high reliability by selectively using write-back control and write-through control for each unit set in advance.

[0002]

2. Description of the Related Art In recent years, the spread of computers has been remarkable, and the amount of data processed by computers has continued to increase. Under such circumstances, development of a high-speed and large-capacity storage device has been strongly desired, and a storage system of hierarchical storage control has been born as one of them. The storage system of the hierarchical storage control will be described with reference to FIGS. FIG. 8 is a diagram showing a configuration example of the system, and FIG. 9 is a diagram showing a data control flow between layers.

The hierarchical storage system 90 shown in FIG. 8 stores a cache storage 91 composed of a cache memory 92 and a cache disk device 93 combined in multiple stages, a disk drive 95, and a plurality of magneto-optical disks 97. A magneto-optical disk autochanger 94 having a slot 96 is provided, and the frequently accessed data is arranged on the cache memory 91 side, while the infrequently accessed data is arranged on the magneto-optical disk autochanger 94 side. A high-speed and large-capacity storage device is realized.

In the hierarchical storage system 90, as shown in FIG. 9, data transfer between devices is performed in line units. Stage-in (transfer from the lower device to the upper device) is executed when requested by the host system, and stage-out (transfer from the upper device to the lower device) is executed when the dirty ratio of each device increases. Runs in the background.

Here, the dirty data indicates data on the cache memory 91 which is not reflected on the magneto-optical disk 97. On the other hand, the clean data is a cache memory 91 having the same value as that on the magneto-optical disk 97.
The above data is shown.

There are various methods for selecting a line to be staged out in each device.
Generally, the segment LRU (Last Recen)
ly Used) algorithm (SLRU) is applied. In this SLRU, the cache memory 91 is prevented from becoming full due to transient data access by leaving the cache memory 91 only when a specific cache line is accessed two or more times.

[0007]

However, in the above-described conventional hierarchical storage control method, (1) when the host system is turned off, the dirty data stored in the volatile cache memory is lost. (2) When the cache disk device fails, the dirty data stored on the disk is lost. (3) The control of the validity / invalidity of the cache storage cannot be designated for each unit defined by a group of at least one or more magneto-optical disks. (4) The data transfer is controlled by a certain data block called a cache line, and the user cannot directly control the stage-in / stage-out of the data. There is a case where the effect of hierarchical storage cannot be exerted because data cannot be transferred at the same time. There were problems such as.

The present invention has been made in view of such circumstances, and a hierarchical storage system that achieves both high speed and high reliability by selectively using write-back control and write-through control for each unit set in advance. And a hierarchical storage control method.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention manages whether data writing should be controlled by write-back or write-through on a unit basis, and thereby, for example, increases the speed. Write-back control is performed for required business data, while write-through control is performed for business data that requires high reliability. It is intended to be.

That is, according to the present invention, it is possible to realize a hierarchical storage system that achieves both high speed and high reliability. In the present invention, it is preferable to further manage the number of hierarchies in the cache storage to which writing is to be performed when performing write-back control. This allows the user to set the hierarchical storage control finely according to the configuration of the cache storage.

Further, the present invention determines whether or not data corresponding to a file for which a reservation has been instructed by a host system is held in a cache storage, and when the data is not held in the cache storage, the data is transferred from the storage device to the cache storage. In addition to taking in data, control is performed so that data corresponding to the file designated for reservation is not saved outside the cache memory.

Thus, in addition to ordinary hierarchical storage control, desired data (data in a file unit, which is a set of data that can be recognized by the user) can be made resident in the cache storage in response to a user request. Become
Access can be speeded up flexibly.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) First, a first embodiment of the present invention will be described. FIG. 1 is a diagram showing a configuration of a hierarchical storage system according to the first embodiment of the present invention.

As shown in FIG. 1, the hierarchical storage system 10 according to the first embodiment exchanges driver software, which operates on an upper system (for driving and controlling the hierarchical storage system 10), control commands and data. Perform The hierarchical storage system 10 includes a host communication control unit 11, a hierarchical storage control unit 12, and a data flow control unit 13.
1. High-speed and large-capacity hierarchical storage control for the cache disk device 22 and the magneto-optical disk autochanger 23 is executed. Also, this hierarchical storage system 1
0 has a unit management table 14 having the format shown in FIG.

In the hierarchical storage system 10, the magneto-optical disk stored in the magneto-optical disk autochanger 23 is a cache storage (cache memory 2) of an intermediate layer.
1 and a flag indicating whether write-through control without using the cache disk device 22) or write-back control using cache storage is to be performed, in advance for each unit, a write cache flag in the unit management table 14. Stored in the field (00: write cache up to cache memory 21 is valid, 01: write cache up to cache disk device 22 is valid, 10: direct write to magneto-optical disk). Note that a unit is defined as a group of at least one or more magneto-optical disks. The value of the write cache flag managed in the unit management table 14 is set by the user when defining a unit.

When a higher-level system issues a data write request to the hierarchical storage system 10, a write request is issued from the driver software to the hierarchical storage system 10. The write request is received by the host communication controller 11. The host communication control unit 11 refers to the unit management table 14 to determine whether the received write target unit (magneto-optical disk) uses cache storage or writes directly to the magneto-optical disk. .

The determination result is notified to the hierarchical storage control unit 12, and the hierarchical storage control unit 12 outputs a write instruction based on the notified determination result to the data flow control unit 13. On the other hand, the data flow control unit 13 transfers the data directly to the magneto-optical disk autochanger 23 according to the instruction of the hierarchical storage control unit 12, for example, when the cache storage is not used, and then notifies the host communication of the end of the write processing. Write processing such as returning to the control unit 11 is performed. Conversely, when using cache storage, after performing data transfer (up to the cache memory 21 or up to the cache disk device) up to the tier included in the instruction from the tier storage control unit 12, a write process end notification is made. Is returned to the host communication control unit 11.

In the hierarchical storage system 10, the data flow control unit 13 writes data to the cache disk device 22 in the background after the end of the write process in order to make the read cache valid.

FIG. 3 is a flowchart showing an operation procedure of the hierarchical storage system 10 according to the first embodiment. When a write request is received from the host system (step A
1) The host communication control section 11 refers to the unit management table 14 to determine whether the received write target unit uses the cache storage or writes directly to the magneto-optical disk, and determines the determination. The result is notified to the hierarchical storage control unit 12 (step A2).

When cache storage is not used (YES in step A3), the hierarchical storage control unit 12 outputs a write instruction to the data flow control unit 13 to directly transfer data to the magneto-optical disk autochanger 23 (step A3). Step A4). On the other hand, when the cache storage is used (NO in step A3), the hierarchical storage control unit 12 issues a write instruction to the data flow control unit 14 to transfer the data to the cache storage (transfer to any hierarchical level) Is output (step A5).

As described above, according to the hierarchical storage system 10 of the first embodiment, the write-back control and the write-through control can be selectively used for each unit, so that both high speed and high reliability can be achieved. It becomes possible.

(Second Embodiment) Next, a second embodiment of the present invention will be described. FIG. 4 is a diagram showing a configuration of a hierarchical storage system according to the second embodiment of the present invention.

In the hierarchical storage system 10, internal data transfer is usually performed in a specific block unit. And
The data transfer unit in the hierarchical storage system 10 is:
Called cache line.

The hierarchical storage system 10 according to the second embodiment
Has a logical-physical conversion unit 15 that converts write data and read data from the host system into cache lines, in addition to the configuration of the hierarchical storage system 10 of the first embodiment described above. The logical-physical conversion unit 15 has a format shown in FIG. 5 for managing information (file designation information) indicating which group of the converted cache line constitutes specific user data (for example, a file name). It has a logical-physical conversion table 16. In addition, the hierarchical storage system 10 of the second embodiment
Has a cache management table 17 having a format shown in FIG. 6 for controlling a cache line.

In this cache management table 17, the stage (cache memory 2)
1 or a stage field (00: cache memory 21, 01: cache disk device 2) for managing whether or not it is stored in the hierarchy of cache disk device 22.
2) and a chain information field for managing line group information.

When a higher-level system issues a file reservation request to the hierarchical storage system 10, the driver software issues a file reservation request to the hierarchical storage system 10. This file reservation request is sent to the host communication controller 11. Received and host communication control unit 1
1 transfers the file reservation request to the logical-physical conversion unit 15. On the other hand, the logical-physical conversion unit 15 determines whether the line corresponding to the requested file exists in the cache storage with reference to the logical-physical conversion table 16.

As a result of the determination, if the line is present in the cache storage (the cache memory 21 or the cache disk device 22), the logical-physical conversion unit 15 sets the hierarchical storage control unit 12 so that the line is not subjected to the stage-out. Notify. Then, the hierarchical storage control unit 12 receiving this notification locks the corresponding line in the cache management table 17. This causes the line to be resident in the cache storage.

On the other hand, if the relevant line is not in the cache storage, the logical-physical conversion unit 15 instructs the hierarchical storage control unit 12 to execute the lowest-layer magneto-optical disk autochanger 23.
To load data into cache storage. Then, the hierarchical storage control unit 12 having received this notification,
A copy instruction is issued to the data flow control unit 13. The data flow control unit 13 transfers the relevant data from the magneto-optical autochanger 23 to the higher-level cache storage (the cache memory 21 or the cache disk device 22) in accordance with the instruction of the hierarchical storage control unit 12, and sends the end notification to the hierarchical storage. Return to control unit 12. Then, the hierarchical storage control unit 12 that has received the end notification locks the relevant line in the cache management table 17 in the same manner as described above, and makes the relevant line resident in the cache storage.

Thereafter, the hierarchical storage controller 12 notifies the logical-physical converter 12 of the completion of the processing, and the logical-physical converter 12 rewrites the logical-physical conversion table 16. FIG.
4 is a flowchart showing an operation procedure of the hierarchical storage system 10 according to the first embodiment.

Upon receiving a file reservation request from the host system (step B1), the host communication control unit 11
This file reservation request is passed to the logical-physical conversion unit 15, and the logical-physical conversion unit 15 determines whether or not the line corresponding to the requested file is in the cache storage with reference to the logical-physical conversion table 16 (step B
2).

If the relevant line exists in the cache storage (YES in step B3), the logical-physical conversion unit 15
The hierarchical storage control unit 12 is notified so that the line is not targeted for stage out. Then, the hierarchical storage control unit 12 that has received the notification sends the cache management table 17
The corresponding line is locked in the cache memory by locking the corresponding line in (step B5).

On the other hand, if the corresponding line is not in the cache storage (NO in step B3), the logical-physical conversion unit 15
It notifies the hierarchical storage controller 12 to load data from the magneto-optical disk autochanger 23 of the lowest layer into the cache storage. Then, the hierarchical storage control unit 12 receiving this notification issues a copy instruction to the data flow control unit 13. In accordance with the instruction from the hierarchical storage control unit 12, the data flow control unit 13 transfers the corresponding data from the magneto-optical autochanger 23 to the upper cache storage (step B4). After that, the hierarchical storage control unit 12
Locks the relevant line in the cache management table 17 to make the relevant line resident in the cache memory (step B5).

Thus, according to the hierarchical storage system 10 of the second embodiment, for example,
By excluding data (file units) reserved in advance from the higher-level system from the target of normal hierarchical storage control,
Enables cache management by user specification.

Since the method of the present invention can be realized as software, it is stored in a computer-readable recording medium such as a floppy disk, an optical disk, or a semiconductor memory as a program that can be executed by a computer. It can be distributed. Then, the computer that has read the contents of the recording medium controls the execution of the read program to realize the above-described processing.

[0035]

As described above in detail, according to the present invention, whether data writing should be controlled by write-back or write-through is managed in units of a unit, so that, for example, a business requiring high speed is required. It is possible to implement a hierarchical storage system that achieves both high speed and high reliability, such as performing write-back control for data of the same type and performing write-through control for business data that requires high reliability. It becomes possible.

Further, by further managing the number of hierarchies in the cache memory to which writing is to be performed when performing the write-back control, the user can finely set the hierarchical memory control according to the configuration of the cache memory. Becomes possible.

Further, by controlling the data corresponding to the file for which the reservation has been instructed by the host system into the cache storage, and controlling the data not to be saved out of the cache storage, the user is provided separately from the normal hierarchical storage control. It is possible to flexibly increase the speed of access to desired data in response to the request.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a hierarchical storage system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a format of a unit management table according to the first embodiment.

FIG. 3 is an exemplary flowchart showing the operation procedure of the hierarchical storage system according to the first embodiment;

FIG. 4 is a diagram showing a configuration of a hierarchical storage system according to a second embodiment of the present invention.

FIG. 5 is a view showing a format of a logical-physical conversion table according to the second embodiment;

FIG. 6 is a view showing a format of a cache management table according to the second embodiment;

FIG. 7 is an exemplary flowchart showing the operation procedure of the hierarchical storage system according to the second embodiment;

FIG. 8 is a diagram showing a configuration example of a storage system of tiered storage control.

FIG. 9 is a diagram showing a data control flow between tiers in a tiered storage control storage system.

[Explanation of symbols]

10: hierarchical storage system, 11: host communication control unit, 1
2 hierarchical storage control unit 13 data flow control unit 14
... Unit management table, 15 ... Logical physical conversion unit, 16
... Logical-physical conversion table, 17 cache line management table, 21 cache memory, 22 cache disk device, 23 magneto-optical disk autochanger.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI G06F 12/12 G06F 12/12 D

Claims (12)

[Claims] 1. A hierarchical storage system in which a cache memory having an access speed higher than that of the magneto-optical disk autochanger is provided at an upper stage of the magneto-optical disk autochanger accommodating a plurality of magneto-optical disks, wherein writing is performed only to the cache memory. Write control data indicating whether to control the writing of data requested by write-back to be executed or write-through to execute writing to the magneto-optical disk each time is defined by a group of at least one or more magneto-optical disks. A hierarchical storage system comprising: a unit management table for storing data in units of a unit; and write control means for controlling data writing based on the unit management table. 2. The cache memory includes a plurality of types of storage devices having different access speeds combined with each other in multiple stages. The unit management table executes the writing when controlling the writing of the data by write-back. 2. The hierarchical storage system according to claim 1, further comprising the number of layers in the cache storage to be stored. 3. A logical-physical conversion table for storing correspondence between data held in the cache storage and files recognized by a higher-level system accessing the hierarchical storage system; A data fetching unit that learns from the logical-physical conversion table whether or not corresponding data is held in the cache storage, and loads the data from the magneto-optical disk into the cache storage when the data is not held in the cache storage. 2. The storage device according to claim 1, further comprising: a hierarchical storage control unit configured to control data corresponding to the reserved file held in the cache storage not to be saved outside the cache storage. 2. The hierarchical storage system according to item 2. 4. In a hierarchical storage system in which a low-speed and large-capacity storage device is provided with a higher-speed and smaller-capacity cache storage than the storage device, a write-back that executes writing only to the cache storage and the storage device A unit management table for storing write control data indicating in which unit the write of requested data is to be controlled by a write-through that executes writing each time in a unit unit preset in the storage device; A write control means for controlling data writing based on the table. 5. The cache storage is configured by combining a plurality of types of storage devices having different access speeds in multiple stages, and the unit management table executes the writing when controlling the writing of the data by write-back. 5. The hierarchical storage system according to claim 4, further comprising the number of layers in the cache storage to be stored. 6. A logical-physical conversion table for storing correspondence between data held in the cache storage and a file recognized by a higher-level system accessing the hierarchical storage system, and a file designated as reserved by the higher-level system. Data fetching means for determining from the logical-physical conversion table whether or not corresponding data is held in the cache storage, and fetching the data from the storage device into the cache storage when the data is not held in the cache storage 6. The storage system according to claim 4, further comprising: a hierarchical storage control unit configured to control data corresponding to the file designated for reservation, which is held in the cache storage, so as not to be saved outside the cache storage. A hierarchical storage system as described. 7. A tiered storage control method for a tiered storage system in which a low-speed and large-capacity storage device is provided with a higher-speed and smaller-capacity cache storage device than the storage device, wherein a write that executes writing only to the cache storage is provided. Managing write control data indicating whether writing of requested data should be controlled by back or by writing through the storage device each time, in units of units, based on the managed write control data Controlling the writing of data. 8. Hierarchical storage in which a plurality of types of storage devices, each of which has a different access speed and a higher speed and a smaller capacity than the storage device, are provided in a multi-stage manner above the low-speed and large-capacity storage device. In the hierarchical storage control method for a system, write control data indicating whether to control writing of data requested by write-back that executes writing only to the cache storage or write-through that executes writing to the storage device each time. Managing the number of hierarchies in the cache memory to perform the writing when controlling the writing of the data by write-back, based on the managed write control data and the number of hierarchies. Controlling data writing by using A hierarchical storage control method. 9. Hierarchical storage in which a plurality of types of storage devices, each of which has a higher speed and a smaller capacity than the storage device and different access speeds from each other, are provided in an upper stage of a low-speed and large-capacity storage device. In the hierarchical storage control method for a system, write control data indicating whether to control writing of data requested by write-back that executes writing only to the cache storage or write-through that executes writing to the storage device each time. Managing the number of hierarchies in the cache memory to perform the writing when controlling the writing of the data by write-back, based on the managed write control data and the number of hierarchies. Controlling the writing of data by Managing the association between the data held in the cache storage and the file recognized by the higher system accessing the hierarchical storage system; and storing the data corresponding to the file instructed to be reserved by the higher system in the cache storage. Acquiring the data from the storage device into the cache memory when the data is not held in the cache memory, and obtaining the data stored in the cache memory when the data is not held in the cache memory. Controlling the data corresponding to the designated file so as not to be saved out of the cache storage. 10. A program for executing a hierarchical storage control on a hierarchical storage system in which a low-speed and large-capacity storage device is provided with a cache storage having a higher speed and a smaller capacity than the storage device. Write control data indicating whether to control writing of data requested by write-back that executes writing only to storage or write-through that executes writing to the storage device each time is managed in units of units, and the management is performed. A computer-readable recording medium recording a program for operating the hierarchical storage system to control data writing based on write control data. 11. Hierarchical storage in which a plurality of types of storage devices having different access speeds, each having a higher speed and a smaller capacity than the storage device, are provided in an upper stage of a low-speed and large-capacity storage device. A program for performing a hierarchical storage control on a system, comprising: writing data requested by either write-back that executes writing only to the cache storage or write-through that executes writing to the storage device each time. Managing the write control data indicating whether to control the unit, and controlling the number of layers in the cache memory to execute the writing when controlling the writing of the data by write-back; and Controlling the writing of data based on the number of layers A computer-readable recording medium on which a program for operating a storage system is recorded. 12. Hierarchical storage in which a plurality of types of storage devices, each of which has a different access speed and a higher speed and a smaller capacity than the storage device, are provided in an upper stage of a low-speed and large-capacity storage device. A program for performing a hierarchical storage control on a system, comprising: writing data requested by either write-back that executes writing only to the cache storage or write-through that executes writing to the storage device each time. Managing the write control data indicating whether to control the unit, and controlling the number of layers in the cache memory to execute the writing when controlling the writing of the data by write-back; and Controlling the data writing based on the number of layers; Manages the association between the data held in the storage and the file recognized by the higher system accessing this hierarchical storage system, and checks whether the data corresponding to the file instructed to be reserved by the higher system is held in the cache memory. Whether or not the file is instructed by the managing correspondence, and when the data is not stored in the cache storage, the data is fetched from the storage device into the cache storage, and the reservation-instructed file stored in the cache storage is A computer-readable storage medium storing a program for operating the hierarchical storage system so as to control corresponding data not to be saved out of the cache storage.