JP2002351622A - Data transfer control method and external storage system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide efficiently perform a data duplex operation by realizing a multiplexed processing of data transfer to the same volume in the case of transferring data from an external storage controller on the original side to an external storage controller on the duplicated side when writing requests from the host device are concentrated on one specific volume in the external storage devices to duplex written data from the host device. SOLUTION: Multiplexed transfer of the data is performed to the same volume viewed from the host device by using a preliminarily defined volume without influencing write from the host device and different from the one specified by the host device as dummy and transferring information via a vacant interface when a further transfer request is given to the volume transferring the data in the case of transferring the data from the external storage controller on the original side to the external storage controller on the duplicated side. This method has effects that transferability of an interface is utilized to the utmost and multiplexed storage of the data is efficiently realized since a bottleneck problem due to congestion of a part of an interface with physically high transferability is dissolved and a vacant path is utilized in such an interface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an external storage device connected to a higher-level device, which stores multiple data in an external storage system connected to another external storage device. The present invention relates to a technique for reducing congestion of an interface for transferring data to a secondary external storage device.

[0002]

2. Description of the Related Art As a method of holding data used by a host device in a plurality of external storage devices, the same data is held. For example, primary and secondary storage units (volumes) are provided under different primary and secondary external storage controllers, and the external storage controllers are connected without passing through a higher-level device, and received by the primary external storage controller. The primary external storage controller issues a write request to the secondary external storage controller so that the data in the primary and secondary storage units match.

As means for matching data, a secondary storage device paired with a volume of a primary storage device unit designated by a write command from a higher-level device for write data from a higher-level device. The primary external storage controller issues a write request to the secondary external storage controller by specifying the volume of the unit, and data is sequentially transferred from the primary external storage controller to the secondary external storage controller in volume units. The method of transferring is generally adopted.

On the other hand, with the recent increase in the amount of data processing,
Similar to the performance of writing data to the primary storage device unit in response to a write request from a higher-level device, there is a demand for improvement in the performance of writing data to the secondary storage device unit in response to a write request from the primary external storage control device.

[0005]

The processing of data input / output on a volume basis is performed by an input / output interface with an operating system (OS) of a host device.
This method has been used since ancient times. For this reason, processing of data input / output on a volume basis also between the primary and secondary external storage controllers seems to be an effective technique in terms of maintaining compatibility.

Here, the term “volume” used to be a concept that physically matches a storage device unit in the past, but recently does not always match a storage device unit as the storage capacity of the storage device unit increases. Became a concept. 1
One storage device unit may include a plurality of volumes, while one volume may include a plurality of storage device units.

If the above-described volume-based processing technology is implemented without any measures, when write requests from a host device are concentrated on a specific one volume, data transfer between the primary and secondary external storage control devices is reduced to a volume. The transfer must be performed in units, and the next data cannot be transferred until the transfer of one data is completed. This is because the transfer to the corresponding volume of the secondary storage unit is processed sequentially. Therefore, only a part of the interface is used. As a result, the physical transfer capability between the primary and secondary external storage controllers cannot be fully utilized, and the performance is not improved. An object of the present invention is to transfer write data received from a host device from a primary external storage control device to a secondary external storage control device, in which write requests from the host device concentrate on one specific volume. Even in such a case, the data transfer control that allows the physical transfer capability of the interface to be utilized by multiplexing the data transfer from the primary volume to the corresponding secondary volume, thereby realizing improved multiplex storage of data. An object of the present invention is to provide a method and an external storage device using the same.

Here, the term "multiplex processing" means that a plurality of interfaces operate at the same time in a macroscopic manner so that the transfer capability of the interfaces is sufficiently exhibited. Each of the plurality of interfaces has a separate microprocessor.

[0009]

An external storage control device (hereinafter referred to as a primary external storage control device) that has received a write command from a higher-level device has the same data as the data stored in its own storage device unit. In order to retain data, data is written to a storage device unit (hereinafter, referred to as a secondary storage device unit) under another external storage control device (hereinafter, referred to as a secondary external storage control device). In an external storage system that implements multiplexing, when data is transferred from the primary external storage controller to the secondary external storage controller, it is asynchronous with the write command that stores the write data received from the higher-level device in the primary volume. The problem is solved by using a control method that enables multiplexed data transfer to the secondary volume and storing the data, and providing the means.

Here, "asynchronous" means that data transfer from the primary external storage controller to the secondary external storage controller is not synchronized with data processing in the primary external storage controller. In other words, this means that the primary external storage controller processes the data without waiting for a response to the effect that the data has been received from the secondary external storage controller.

In transferring data from the primary external storage control device to the secondary external storage control device, for example, when a write request from a higher-level device is concentrated on one specific volume, a higher-level device provided in advance is used. When information is transferred to a secondary volume that is paired with a primary volume that does not affect writing from the primary device or that prohibits writing from the higher-level device, control information is separated. The problem is solved by providing means for converting the control information into an information suitable for the secondary external storage device in the secondary external storage control device.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration example (conceptual diagram) of an external storage system. An external storage system connected to the host 1, which is a higher-level device, includes a primary disk controller 2
And a secondary disk control device 4.

The primary disk controller 2 includes a channel port 10 connected to the host 1 by an interface cable 13, a microprocessor 6 connected thereto, a cache memory 8, and a plurality of disk volumes 2.
5 is connected to the secondary disk controller 4 via the primary channel port 11.

Although each of the channel ports 10 and 11 and the microprocessor 6 is shown in FIG. 1 as if it were one, the information transmission path of the channel port 10, the microprocessor 6 and the channel port 11 is , May be provided. In this case, the secondary disk control device 4 is also provided with a plurality of information transmission paths for the channel port 12 and the microprocessor 7, so that the information to be transferred can be smoothly multiplexed.

The secondary disk controller 4 includes a secondary channel port 12 connected to an interface cable 14.
Is connected to the primary-side disk control device 2. Positive channel port 11, interface cable 14,
The secondary channel port 12 forms a channel between disk controllers. Interface cable 14
May be any information communication network. The secondary disk control device 4 includes a microprocessor 7 connected to the channel port 12, a cache memory 9, and a secondary disk device 5 having a plurality of disk volumes 26.

The microprocessor 6 of the primary disk control device 2 includes a command processing unit 15, a schedule processing unit 1
6, a data transfer processing unit 17 and a destage processing unit 18, and the cache memory 8 includes a queue 19. The signal processing units of the command processing unit 15, the schedule processing unit 16, the data transfer processing unit 17, and the destage processing unit 18 are functions implemented by a microprogram executed by the microprocessor 6 built in the primary disk control device 2. It is a block. Each operation and processing will be described later. The microprocessor 7 of the secondary disk control device 4 includes a command processing unit 23, a destage processing unit 24
Each of these signal processing means is a functional block realized by a microprogram executed by the microprocessor 7 incorporated in the secondary disk control device 4.
Each operation process will be described later.

FIG. 2 is a conceptual diagram showing an example of a volume pair for which primary and secondary coincidence is to be achieved in the external storage system of FIG. Also, the path 14a, the path 14b,
Path 14c and path 14d are interface cables 1
4 represents a logical path. Although four paths are defined in this embodiment, any number of paths may be used in an actual system.

Volume 2 in Primary Disk Unit 3
5a is a volume 26a in the secondary disk device 5.
To form a pair a that matches the positive and the negative.
And 26b, 25c and 26c, and 25d and 26d form a pair b, a pair c, and a pair d, respectively. However, the volume 25b and the volume 2 in the primary disk device 3
5c is a volume which is not used by the host 1 or whose volume is prohibited from being read / written.
Is defined as a dummy pair without having to actually try to match the two. Since the volumes of these dummy pairs b and c are not recognized by the host 1, the volumes need not be recognized by the host in order to effectively use the volume capacity, and may be the minimum capacity that can be defined as a volume. Absent. For example, a definition of only the capacity for one cylinder may be used. Further, these dummy pairs b and c are defined as a dummy for the pair a. The definition of these dummy pairs is performed by an operation from the console screen of the primary disk device 3, as in the definition of ordinary pairs.

Next, the processing of the operation will be described in detail with reference to FIG. The write request issued from the host 1 is received by the channel port 10 of the primary disk control device 2,
The command is sent to the microprocessor 6 and sent to the command processing unit 15.
Executed in The command processing unit 15 writes the write data sent from the host 1 to the cache memory 8 to generate the write data 22, and has a one-to-one correspondence with the write data 22, and specifies a write destination volume number or the like designated by the host. Is created. When the control information 21 is set in the queue 19, a write completion report is made to the host 1, and thus write requests from the host are sequentially accepted.

FIG. 3 shows an example in which five sets of write data 22a to 22e from the host 1 are waiting on the cache memory 8 of the primary disk controller 2. In this example, the write data 22a, 22c,
22d and 22e are write data to the volume 25a and volume # 1a of the primary disk device 3 in FIG. 2, and only the write data 22b is write data to the volume 25d and volume # 1d of the primary disk device 3. is there.

Each of the write data 22a to 22e has one-to-one control information 21a to 21e.
Is set in the queue 19. Each control information 21 includes control information such as a write destination volume number.

Next, the schedule processing section 16 of the microprocessor 6 sequentially retrieves the control information 21 in the queue 19 and writes the volume number to be written to the primary disk device 3 to the paired secondary disk device 5. And transfers the control to the transfer processing unit 17 (FIG. 1). In the transfer processing unit 17, the control information 21 and the write data 22 are transmitted to the secondary disk control device 4 by the channel port 11, the interface 14, and the channel port 12.
To transfer through.

FIG. 4 shows an example of a method for transferring the control information 21 and the write data 22 shown in FIG. First, the control information 21a extracted from the queue 19 includes the volume 25a of the primary disk device 3, the volume 26a of the secondary disk device 5 paired with the volume # 1a,
The data is transferred to the secondary disk controller 4 via the logical path 14a together with the write data 22a to the volume # 2a.

Next, the control information 21b extracted from the queue 19 is stored in the secondary disk device 5 paired with the volume 25d and volume # 1d of the primary disk device 3.
Logical volume 1 used by the pair a together with the write data 22b to the volume 26d and volume # 2d.
The data is transferred to the secondary disk control device 4 through the logical path 14d other than the logical path 4a.

Next, the control information 21c extracted from the queue 19 is stored in the volume 25a of the primary disk device 3,
The write data 22c and the write data 22c are transferred to the secondary disk control device 4 to the volume 26a and the volume # 2a of the secondary disk device 5 paired with the volume # 1a. However, regarding writing to the volume 26a and volume # 2a of the secondary disk device 5,
The control information 21a 'and its write data 22a are being transferred, and the logical path 14a is also used. Therefore, the pair b (FIG. 2), which is a usable dummy pair, is used. In the example of FIG. 2, volume # 1b and volume # 1c are
The host 1 is set not to be used. The microprocessor 6 (FIG. 1) converts the write destination volume to the volume 26b (volume # 2b) of the secondary disk device 5, and transfers it to the secondary disk control device 4 using the logical path 14b together with the write data 22c. .

Similarly, the control information 21d extracted from the queue 19 next uses the pair c which is an unused dummy pair (FIG. 2), and sets the write destination volume to the volume 26c of the secondary disk device 5. , Volume # 2c
And the data is transferred to the secondary disk control device 4 using the logical path 14c together with the write data 22d.

The above is the case where the number of volumes 25 and the number of logical paths 14a to 14d constituting the interface 14 are 4, but if the number of logical paths is increased, the number of dummy pairs can be increased. The transfer is performed more smoothly.

The destage processing section 18 is executed asynchronously with each of the above-mentioned processes. The destage processing unit 18 stores each write data 22 stored in the cache memory 8 in a target volume 25 of the primary disk device 3.

The write request issued from the primary disk controller 2 is received by the microprocessor 7 of the secondary disk controller 4 via the channel port 11, the interface 14, and the channel port 12, and the command processing 23 Be executed. In the command processing 23, the microprocessor 7 writes the control information 21 'transferred from the primary disk control device 2, for example, the write destination volume of the control information 21a', 21b ', 21c', 21d 'as shown in FIG. To the original destination volume,
Write data 22 (22a, 22b, 22c, 22d)
At the same time, the data is written to the cache memory 9, a write completion report is sent to the primary disk control device 2, and the system waits in a state of sequentially receiving write requests.

FIG. 5 shows that the write data 22 from the primary disk control device 2, for example, the write data 22a, the write data 22b, the write data 22c, the write data 22d, and the like from the primary disk control device 2 are stored in the cache memory 9 of the secondary disk control device 4.
It is a figure showing the concept in which write data 22e was written.

The write data 22a corresponds to the control information 2 shown in FIG.
1a and the write data 22a are stored in the cache memory 9 so that the write destination volume is set with the control information 21a ″ of the volume 26a and volume # 2a. The cache memory of the primary disk control device 8 is converted into control information 21a ″ and volume # 2a in the cache memory 9 of the secondary disk control device. The write data 22b is stored so as to be set with the control information 21b ″ that sets the write destination volume to the volume 26d and the volume # 2d. Similarly, the write data 22c, 22d, and 22e respectively Volume 26a, control information 21c ″ of volume # 2a, volume 26a,
The control information 21d "of the volume # 2a and the control information 21e" of the volume 26a and the volume # 2a are stored in the cache memory 9 as a set. Finally, the destage processing unit 24 is executed asynchronously with each of the above-described processes, and stores the respective write data 2 in the cache memory 9.
2 (22a, 22b, 22c, 22d, 22e) are stored in the target volume 26 of the secondary disk device 5.

[0032]

According to the present invention, in the process of transferring the write data received from the higher-level device to the secondary external storage control device, the higher-level device which is different from the volume designated by the higher-level device, By using a volume that does not affect the same volume and enabling multiple transfers to the same volume, the effect of improving the write performance can be obtained.

By converting control information, performing multiplex transfer with data through an unused interface, and returning to the original control information at the transfer destination, the hardware resources of the system can be effectively used, and This has the effect of improving performance.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration example of an external storage system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a specific example of a pair state of volumes for which primary and secondary matches are to be made in the external storage system of FIG. 1;

FIG. 3 is a conceptual diagram of data processing of a primary disk control device 2 in the external storage system of FIG. 1;

FIG. 4 is a conceptual diagram of data transfer processing between primary and secondary disk controllers in the external storage system of FIG. 1;

FIG. 5 is a conceptual diagram of data processing of a secondary disk control device 4 in the external storage system of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Host, 2 ... Primary disk controller (1st external storage controller), 3 ... Primary disk controller, 4 ... Secondary disk controller (2nd external storage controller) Device)
..Secondary disk devices, 6, 7...
8, 9: Cache memory, 10: Channel port, 11: Primary channel port, 12: Secondary channel port, 13, 14: Interface cable, 15: Command processing unit , 16 ... schedule processing unit, 17 ... data transfer processing unit,
18: destage processing unit, 19: queue,
21 ... control information, 22 ... write data,
23 command processing unit 24 destage processing unit 25 primary disk device volume 26 secondary disk device volume 14a logical paths a and 14b logical paths b, 14c: Logical path c, 14d: Logical path d, 25a to 25d: Primary disk device volume, 26a to 26d: Secondary disk device volume
21a to 21e ... control information, 22a to 22e ...
Write data, 21a 'to 21e' ... control information, 21
a "to 21e" ... control information.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shigeru Kishiro 322-2 Nakazato, Odawara City, Kanagawa Prefecture Inside the RAID Systems Division of Hitachi, Ltd. Hitachi Systems, Ltd. RAID Systems Division (72) Inventor Nobuaki Nakamura 6-81 Onoecho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi Software Engineering Co., Ltd. In-house F-term (reference) 5B018 GA10 HA03 MA12 5B065 BA01 CA07 CC02 CC08 CH20 ZA01

Claims (8)

[Claims] A first external storage device connected to a higher-level device, comprising a first external storage control device connected to the higher-level device and a storage device unit connected to the first external storage control device; A second external storage control device connected to the external storage control device and a second external storage device having a storage device unit connected to the second external storage control device, wherein data of a volume in the first external storage device is stored. In an external storage system for copying to a volume in the second external storage device, control information of a volume designated when writing from the higher-level device to the first external storage device is converted into another control information. By converting and transferring the data from the first external storage control device to the second external storage control device, data accompanying the control information is stored in a volume in the second external storage device. External storage system, wherein the door. 2. The external storage system according to claim 1, wherein the first external storage control device includes a command processing unit that writes the write data received from the higher-level device to a cache, and the higher-level device specifies a write command. A schedule processing unit that converts the write data into a volume number different from the write destination volume of the first external storage device; and writes the write data written in the cache in units of volume numbers asynchronously with a write command from a higher-level device. The transfer processing unit according to claim 1, further comprising: a transfer processing unit that transfers the data written in the cache to the second external storage control device; and a destage processing unit that writes the data written in the cache to the volume asynchronously with a write command from the host device. External storage system. 3. The external storage system according to claim 1, wherein the second external storage control device sends the write destination volume number transferred from the first external storage control device to the first external storage device. Returning to the volume number of the volume of the second external storage device that is paired with the volume specified when writing to the storage device, the data accompanying the write destination volume number,
The external storage system according to claim 1, further comprising: a command processing unit that writes data to a cache; and a destage processing unit that writes data written to the cache to a volume asynchronously with the command processing unit. 4. The first external storage system according to claim 2,
Means for defining a dummy pair subordinate to a specific volume pair between the first external storage device and the second external storage device. An external storage system, characterized in that: 5. The first external storage system according to claim 4, wherein
The external storage system according to claim 1, wherein a volume number different from a write destination volume of said first external storage device specified by a higher-level device by a write command is a volume of said dummy pair. 6. The first external storage system according to claim 5,
In the external storage control device of the above, a specific volume pair between the first external storage device and the second external storage device and a plurality of dummy pairs subordinate thereto The data transfer control from the first external storage device to the second external storage device is multiplexed by executing the data transfer process for each volume on a separate microprocessor having a plurality of microprocessors. External storage system. 7. The first external storage system according to claim 4,
In the external storage control device, the capacity of the volume defined as the dummy pair can be arbitrarily set irrespective of the capacity that can be recognized by a higher-level device. 8. A first external storage device connected to a higher-level device, comprising: a first external storage control device connected to a higher-level device, and a storage device unit connected to the first external storage control device. A data transfer control method for an external storage system, comprising: a second external storage control device connected to the external storage control device, and a second external storage device having a storage device unit connected thereto. A first step of starting to copy data of a volume in the first external storage device to a volume in the second external storage device, and writing from the higher-level device to the first external storage device. A second step of converting the control information of the volume designated in the second step into another control information; and transferring the other control information from the first external storage controller to the second external storage controller. An external storage system comprising: a third step; and a fourth step of storing data accompanying the other control information in a volume in the second external storage device.