JPH08147111A - Extended constitution method for disk array device - Google Patents

Abstract

PURPOSE: To easily increase the number of disk devices in the range of a maximum constitution without saving data and parities of existing disk devices neither calculating the parities again. CONSTITUTION: A virtual address map table 24 is generated where addresses for storage of data and parities are determined in accordance with the maximum constitution of N(=5) disk devices. In the initial constitution consisting of, for example, M(=3) disk devices 1, 2, and 5, an address conversion table 26 is generated which assigns the same storage addresses as the virtual address map table 24 to data and parities of (M-1) (=2) disk devices 1 and 2 and collectively assigns storage addresses for parities of disk devices, which don't actually exist, in the virtual address map table 24 to the other shadow disk device 5. In response to the input/output request from a host device 10, the address conversion table 26 is referred to perform data read or data write and parity update. When a disk device 4 is added, this device 4 is initialized, and the parity of the shadow disk device 5 is written back and is initialized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of expanding a disk array device in which an expansion of a disk device is planned. In particular, the expansion of a disk array device that can be expanded without the need to save the data of the existing disk device. Regarding the configuration method.

[0002]

2. Description of the Related Art In recent years, nonvolatile storage, large capacity, high speed of data transfer, etc. have been required as an external storage device of a computer system, and a disk array device has been attracting attention as one satisfying these requirements. FIG. 18 shows a conventional disk array device, in which a host computer 10 is provided with a disk array control device 12, and a disk array control device is provided with a disk array 14 in which, for example, five disk devices 1 to 5 are connected in parallel. Here, the disk array has a rank that is an array of a plurality of disk devices that form the array, and has ports that connect the disk devices 1 to 5, and in the case of FIG. 18, has a 5-port 1-rank structure.

As such a disk array device, the classifications of RAID 1 to 5 are conventionally known. Among them, RAID3 and RAID5 are generally put into practical use.
RAID 3 has a fixed disk device for storing parity and is suitable for accessing a large amount of data such as file data. RAID 5 is a distribution of disk devices that store parity, and is suitable for transaction processing that requires reading and writing in sector units. The present invention is
The target is a disk array device of AID5.

The capacity of the disk array device is determined by the number of disk devices to be accessed in parallel. Therefore, when it is desired to increase the capacity of the disk array device, it is general to add the disk arrays 14-1 and 14-2 in rank units so as to form a two-rank configuration, as shown in FIG. However, the number of ranks does not change because the scale increases too much in rank units, and it is also necessary to expand in units of disk devices to add the disk devices 6 as shown in FIG.

[0005]

However, when it is desired to expand the disk array device in units of disk devices, the data and parity of the existing disk device are temporarily saved in another storage device, and the disk device is added. It is necessary to relocate and write back the data and parity that were saved later. For this reason, there is a problem that the expansion work cannot be performed while the existing data can be accessed, and the computer system must be stopped when the disk array device is added.

Therefore, in the conventional RAID5 disk array device, data and parity that do not need to stop access to existing data as shown in FIG. 21 are stored ("Nikkei Watcher IBM version 1992.9"). ．
No. 14 "IBM 9337 Disk Array Subsystem). That is, data and parity storage addresses (sector addresses) are assigned to the existing disks 1 to 5, and only the data storage addresses are assigned to the added disk device 6.

Therefore, when the disk device 6 is expanded, all the storage addresses of the disk device are initialized to zero data, and when the expansion is completed and the address map table including the disk device 6 is changed, the existing disk The data and parity of the devices 1 to 5 can be used as they are to shift to the access including the additional disk device 6.

However, the expansion of the disk array unit of the disk array device of FIG. 21 is based on the assumption that an array is composed of five disk devices from the beginning, and the parity is not stored in the additional disk device. Eliminates the need to save data and generate new parity associated with expansion,
There was a problem that it could not be applied to expansion in a smaller disk array device.

Further, when the number of disk devices to be added increases, the distributed storage of parity is not performed in the added disk devices, so that the merit of RAID5 in which different disk devices can be accessed in parallel for the same sector address is reduced. There was also. The present invention has been made in view of the above conventional problems, and it is necessary to add a disk device in the range of a predetermined maximum configuration to save the data and parity of the existing disk device and recalculate the parity. It is an object of the present invention to provide a method for expanding and configuring a disk array device for RAID5 that can be easily performed without the above.

[0010]

FIG. 1 is a diagram illustrating the principle of the present invention. First, the present invention is directed to a disc suspension control device 12
On the other hand, it is an expanded configuration method of a disk array device in which N disk devices, for example N = 5, are connected in parallel in a maximum configuration.

First, the disk device of FIG.
The virtual address map table 24 of FIG. 1B, which defines the addresses for storing data and parity, is created in advance in accordance with the maximum configuration of a table. The initial configuration is a configuration that can be expanded by M disk devices that are less than the maximum configuration number N and are in a range of 3 or more. For example, M = 3 disk devices 1, 2, and 5 have the minimum configuration.

In the configuration state in which M = 3 disk devices 1, 2 and 5, the storage address of data and parity for (M-1) = 2 disk devices 1 and 2 is the virtual address map table 24. The remaining one disk device 5 is defined as a shadow disk device, and the virtual address map table 24 is added to the shadow disk device.
The address conversion table 26 for allocating the storage address of the parity that does not actually exist in the disk device in the above is created.

Then, in response to an input / output request from the higher-level device 10, the address conversion table 26 is referenced to read or write data and update the parity. First M = 3
When the number of disk devices that had been set is (M + 1) = 4, the storage addresses corresponding to the virtual address map table 24 of the added disk device 3 are initialized as in the physical address map of FIG. 1B. . Next, the parity of the shadow disk device 5 is written back to the additional disk device 3 according to the virtual address map table 24, and the storage address of the shadow disk device 5 after the writing back is initialized.

Further, the address conversion table 26 is set to (M
1) corresponding to the expanded configuration of four disk devices
The conversion contents of the physical address map of (D) are changed, and the changed address conversion table 26 is referred to in response to the input / output request from the higher-level device 10 to read or write data and parity of (M + 1) disk devices. Update.

The virtual address map table 24 is created so that one disk device can be used as a spare disk device in an empty state at the maximum configuration using N disk devices. Also, the virtual address map table 24
May be created such that all the disk devices are enabled and the spare disk device is not used during the maximum configuration using N disk devices.

The virtual address map table 24 is (N
-1) Store data and parity in one disk device,
The remaining one disk device can be created so that only data is stored. Further, when the number of disk devices reaches the maximum configuration of N units due to the addition, the address conversion table 26 is deleted and the disk device 1 is processed according to the virtual address map table 24 in response to the input / output request from the host device.
Read or write data and update the parity.

[0017]

According to the present invention, in a disk array device composed of M expandable disk devices, a virtual address map table at the maximum configuration using N disk devices in the disk array controller is provided (however, 3 ≦ M
≦ N), the data sent from the host device is stored in the physical address of the disk device as it is according to the virtual address map table, and the parity generated from the data is distributed to N disk devices according to RAID5. Stored. However, since there are only M actual disk devices, the parity that has no disk device to be stored is focused on one of the disk devices that should originally store data as a shadow disk. Store.

Therefore, at the time of adding a disk device, zero data is written to the additional disk device for initialization, a logical disk device on the virtual address map is allocated, and the parity to be stored in the additional disk device is stored in the shadow disk device. Data is written to the empty disk area of the shadow disk device after the transfer. Then, the address conversion table is recombined so as to be compatible with the disk array after adding the disk device.

Further, the virtual address map table differs depending on whether or not a spare disk device is provided in the maximum configuration. If the mode having the spare disk device in the maximum configuration is selected, the spare device controller is activated at the time when N disk devices are prepared to prepare for the failure of the disk array.

[0020]

【Example】

<Contents> (1) Operating environment (2) When the spare disk unit is not used in the maximum configuration (3) When the spare disk unit is used in the maximum configuration (4) Modification when the spare disk unit is not used in the maximum configuration Embodiment (5) Extended configuration processing of the present invention FIG. 2 is a block diagram showing an embodiment of a disk array device to which the extended configuration method of the present invention is applied.

In FIG. 2, the disk array device of the present invention comprises a disk array controller 12 and a disk array 1.
It is composed of 4. The disk array controller 12 is provided with a host interface controller 18, MPU 16, device interface controller 20, and data transfer controller 22. The host interface controller 18 of the disk array controller 12 is connected to the host computer 10 via the host interface cable 32.

Further, the device interface controller 20
Is, for example, five disk devices 1 to 1 provided in the disk array 14 via the device interface cable 34.
5 are connected in parallel. Here, the connection ports of the disk devices 1 to 5 of the disk array 14 are represented by ports P1 to P5. MPU1 of disk array controller 12
The virtual address map table 24 and the address conversion table 26 are connected to the data No. 6. The virtual address map table 24 defines storage addresses in sector units of the disk devices 1 to 5 in the maximum configuration with five disk arrays 14 as shown in the figure.

Therefore, the MPU 16 includes the disk devices 1 to
In the maximum configuration of 5 units of 5, the requested block is divided into sector blocks of the disk devices 1 to 5 based on the input / output request from the host computer 10 by designating the logical block number, and the sector blocks are allocated. The position is obtained by referring to the virtual address map table 24, and recording or reproduction is performed in data units divided into sector blocks at corresponding storage addresses in the disk devices 1-5.

The address conversion table 26 defines the storage sector address at the stage of expansion until the maximum configuration of less than 5 disk arrays 14 is reached. The expanded configuration method of the present invention requires at least three disk devices. Therefore, the minimum configuration is such that the disk devices of the disk array 14 are, for example, three disk devices 1 and 2, and the disk device 5. Then, with respect to the minimum three disk devices 1, 2, and 5, one disk device can be added in order of the disk device 3 and the disk device 4.

The address conversion table 26 is the virtual address map table 24 in each of the configurations of three disk devices in the minimum configuration and four additional disk devices.
Is generated from. Generally speaking, the extended configuration of the present invention is as follows. When the maximum number of disk devices is N, the number of actual disk devices from 3 to (N-1) is M, and the initial configuration is M. It is possible to expand the initial configuration to the maximum configuration of N units.

Further, the contents of the virtual address map table 24 provided in the disk array control device 12 differ depending on whether or not one disk device in the maximum configuration of five is used as a spare disk device. That is, when the spare disk device is not used with the maximum five devices, the five disk devices 1 to 5 provided in the disk array 14 are used.
A virtual address map table 24 is created for.

On the other hand, when one of the maximum five disks is used as a spare disk device, for example, among the five disk devices 1 to 5 provided in the disk array 14, a disk is used as a spare disk device. When the device 5 is used, the virtual address map table 24 is created for the remaining four disk devices 1 to 4. (2) When the spare disk device is not used in the maximum configuration FIG. 3 is an explanatory diagram of the virtual address map and the physical address map when the spare disk device is not used in the maximum configuration of the five disk arrays 14 in FIG. There is, as an example, a case where three disk devices 1, 2 and 5 having a minimum structure are mounted as an initial structure.

FIG. 3A is a virtual address map in which storage addresses are divided into sector units for each of the disk devices 1 to 5 as shown in the figure. For example, in the case of the disk device 1, the storage addresses are shown. In "1-1", the first number indicates the disk device and the second number indicates the sector address of the data. Normally, the size of a logical block which is an access unit of the host computer is equal to the sector size which is an access unit of the disk devices 1-5.
For example, if the logical block is 4 KB, the sector size is also 4 KB.

In RAID 5, the parity is distributed to different disk devices for different sector addresses. In FIG. 3A, the parity is circulated counterclockwise. That is, the sector address 1 stores the parity P1 in the disk device 5, the sector address 2 stores the parity P2 in the disk device 4, and the sector address 3
The parity P3 is stored in the disk device 3, the parity P4 is stored in the disk device 2 at the sector address 4, the parity P5 is stored in the disk device 1 at the sector address 5, and the disk device 5 is returned to the disk device 5 at the sector address 6.

To such a virtual address map of FIG. 3A, only three disk devices 1, 2, and 5 are actually mounted, and these three disk devices 1, 2, and 5 are mounted.
To store data and parity using
The physical address map of (B) must be used. The physical address map has the same contents as the virtual address map for the disk devices 1 and 2. In addition to this, the remaining one disk device 5 is used as a shadow disk device 5.

In this shadow disk device 5, there are disk devices 3, 4, 5 which do not exist in the virtual address map.
Parities P1 to P3 and P6 to P8 stored in each
Are stored together. Therefore, even if three disk devices are insufficient for the maximum configuration, as for the parity, all the parities P1 to P8 are actually stored as in the virtual address map in the maximum configuration. This FIG. 3 (B)
The state of the physical address map of is obtained by the address conversion table 26 of FIG.

FIG. 4 shows initialization processing and parity write-back for the expanded disk device 3 when one disk device 3 is expanded in the mounted state of the physical address map of FIG. 3B. When the disk device 3 is newly added, the disk device 3 is first initialized to zero data. Subsequently, referring to the virtual address map of FIG. 3A, the storage addresses of the parities P3 and P8 assigned to the added disk device 3 are recognized and stored in the shadow disk device 5 corresponding to this parity storage address. The existing parities P3 and P8 are written back to the added disk device 3, respectively.

FIG. 5 shows a state after the parities P3 and P8 are written back to the added disk device 3, and after the writing back is completed, the storage addresses of the sector addresses 3 and 8 of the shadow disk device 5 are zero data. Initialize with. Further, the address conversion table 26 in the state of FIG. 3B is rewritten in order to enable conversion to the physical address map in the expanded state of the disk device 3. As a result, all the initialization processing by adding the disk device 3 is completed, and in the operating state after the addition, the three disk devices 1, 2, 3 and the shadow disk device 5 as shown in FIG. 6 are used. Data and parity are stored.

When it is desired to add more disk devices 4 from the state of FIG. 6, initialization of the additional disk device 4 and parity P2, P7 from the shadow disk device 5 are performed in the same manner as shown in FIGS. Writing back and initialization of the shadow disk device 5 after writing back are performed, and finally the address translation table 26 is rearranged. When the disk device 4 is added, the shadow disk device 5 finally makes the parity P1 and P6 of the disk device 5 of the virtual address map.
However, the other sector addresses are only 0.

Therefore, the expansion of the disk device 4 is the same as the expansion to the maximum configuration of 5. In this case, the contents of the physical address map become the same as the contents of the virtual address map of FIG. 3A, so the address translation table 26 is deleted and the recording of data and parity based only on the virtual address map table 24. Play. (3) When a spare disk unit is used in the maximum configuration Fig. 7 shows a case in which five disk units with the maximum configuration are mounted.
FIG. 3 is a virtual address map when a disk is used as a spare disk device and a physical address map in an initial configuration when three disk devices are mounted. First, in the virtual address map of FIG. 7A, since the disk device 5 is used as a spare disk device, parity and data are not allocated and four disk devices 1 to 4 are targeted for R.
A sector address for data storage and a parity storage address are set according to AID5.

FIG. 7B is a physical address map when three disk devices 1, 2 and 5 are mounted. The disk devices 1 and 2 are disks for storing data and parity, and the maximum configuration is 5 units. The disk device 5 which is scheduled to be used as a spare disk device in 1 above is called a shadow disk device 5. Even in this physical address map,
For the disk devices 1 and 2, the same data and parity storage addresses as the virtual address map are set,
Parity P stored in the disk devices 3 and 4 of the virtual address map which is not installed in the shadow disk device 5
1, P2, P5, and P6 are stored together, and zero data is put in an address where parity is not stored.

The address translation table 26 in the initial configuration of the disk devices 1, 2 and 5 incorporates the translation contents of the physical address map of FIG. 7B, and addresses in response to input / output requests from the host computer 10. Data is recorded and reproduced by referring to the conversion table 26. FIG.
Shows initialization and parity write-back when the disk device 3 is added. First, all addresses of the added disk device 3 are initialized to zero data. Next, FIG. 7 (A)
The virtual address map of the disk device 3 is referred to, and the parities P2 and P6 of the sector address 2 and the sector address 6 are referred to.
Is recognized, and the parities P2 and P6 are written back to the additional disk device 3 from the sector addresses 2 and 6 of the shadow disk device.

FIG. 9 shows that the additional disk device 3 has a parity P.
2, P6 is in a state after being written back, and zero data is stored in the sector addresses 2 and 6 of the shadow disk 5 which has been written back to be initialized. And finally, Figure 1
As in 0, a sector address for data storage is assigned to the additional disk device 3, and the address conversion table 26 is recombined with the contents of this physical address map to end the expansion process. After the expansion is completed, the disk array 14 may be accessed using the address conversion table 26 having the contents of the physical address map of FIG. (4) Modified example in the case where the spare disk device is not used in the maximum configuration FIG. 11 shows a virtual address map and a physical address map when the spare disk device is not used in the maximum configuration of 5 disk devices, as in FIG. Yes, as in the virtual address map of FIG. 11A, in the maximum configuration, the address setting is performed so that the disk devices 1 to 4 store data and parity, but the disk device 5 stores only data. It is characterized by

Due to the setting of the virtual address map as described above, in the embodiment of FIG. 3, a zero data empty area is generated in the shadow disk device when the size is less than the maximum configuration.
In the embodiment of FIG. 11, the empty area of the shadow disk device is eliminated to improve the usage efficiency of the disk device. FIG. 11B is a physical address map of the mounted state of the three disk devices 1, 2, and 5. For the disk devices 1 and 2, the address setting of data and parity similar to the virtual address map is performed,
A disk device 5 that stores only data in the virtual address map is assigned to the shadow disk device, and the parities P1 and P of the disk devices 3 and 4 not mounted are allocated.
2, P5, P6, and storage of sector addresses 2-3, 1-4, 2-7, 1-8 that cannot be used in the storage of parity P3, P4, P7, P8 in the disk devices 1 and 2 respectively. The address is set.

Therefore, even if the disk devices 1 and 2 store the parities P3 and P8, the shadow disk device 5
Due to the existence of, it is possible to obtain a recording state equivalent to that used for all data storage without substantially storing parity. FIG. 12 shows initialization and parity write-back when the disk device 3 is added. That is, zero data is put into all addresses of the added disk device 3 for initialization. Next, referring to the virtual address map of FIG. 11A, knowing the sector addresses 2 and 6 which are the parity storage addresses of the disk device 3, the shadow disk device 5 adds the parity P2 and P6 from the same sector address to the additional disks. Write back to device 3.

FIG. 13 shows a state after writing back the parities P2 and P6 to the additional disk device 3, and after writing back, zero data is put in the sector addresses 2 and 6 of the shadow disk device 5 for initialization. . Finally, as shown in FIG. 14, the sector addresses 2 and 6 initialized by the zero data of the shadow disk device 5 are referred to the virtual address map of FIG.
Set -2 and 3-6. Then, the address conversion table 26 of FIG. 2 is rearranged so that the conversion contents of the physical address map of FIG. 14 are obtained. (5) Extended Configuration Processing of the Present Invention The flowchart of FIG. 15 is a setup processing for creating the virtual address map table 24 and the address translation table 26 of FIG. First, step S1
Then, the parity stripe mode setting for assigning the parity to a plurality of disk devices is performed. This setting mode includes modes 1 to 3. Mode 1 is a use mode of the spare disk device (spare disk device) of FIG. 7, mode 2 is a spare disk device non-use mode A of FIG. 3, and mode 3 is a spare disk in the modified embodiment of FIG. The non-use mode B is set.

Then, the process proceeds to step S2 and step S1.
The virtual address map table 24 is created in accordance with the contents of the mode setting set in. That is, the virtual address map of FIG. 7A is created in the setting of mode 1, the virtual address map of FIG. 3A is created in mode 2, and the virtual address map of FIG. A virtual address map of (A) is created.

Next, in step S3, it is checked whether or not the number of mounted disk devices is less than the maximum configuration N = 5.
If the number is less than 5, the process proceeds to step S4 and the shadow disk device is set. That is, in the spare disk use mode of mode 1, the spare disk is used as the shadow disk device. In the spare disk non-use mode of mode 2 and mode 3, a specific one is set as the shadow disk device.

Subsequently, the process proceeds to step S5, and the address conversion table 26 is created so that the conversion contents of the physical address map determined by the mounted disk device at that time are obtained.
FIG. 16 shows a data write process in response to a write request from the host computer 10 after the setup process of FIG. 15 is completed. First, when write data is received from the host computer in step S1, the virtual address map table 24 is referenced in step S2, and the sector address for data rewriting is retrieved as the parity address of the disk device to which parity storage allocation is performed. To do.

Next, in step S3, the address conversion table 26 is converted into a parity address on the physical address map, and in step S4, the parity is read from the corresponding disk device. Then, in step S5, the new parity is calculated based on the new data and the old parity. In step S6, the data is first written to the disk device, and then in step S7, the calculated new parity is written to the disk device. Write.

On the other hand, in the data read process, the sector address on the physical address map is obtained by referring to the address conversion table 26 and read. Further, when an uncorrectable error occurs in the read data from the corresponding sector address, the data and parity of the same sector address of another disk device is read to restore the read data in error, and this is restored. It will be transferred to the host computer 10.

FIG. 17 shows expansion processing when a disk device is added in a mounted state of a disk device of less than the maximum configuration. First, if one disk device is added in step S1, the additional disk device is initialized in step S2. That is, all zero data is written in the sector address of the additional disk device. Succeedingly, in a step S3, it is checked whether or not the mounted disk devices have reached the maximum configuration N = 5 units.

If the number is less than 5, the address conversion table is rearranged in step S4, the parity is written back from the shadow disk device to the additional disk device in step S5, and the writing back is completed in step S6. Stores zero data in the free area of the shadow disk device.
Here, in the modified embodiment in which the spare disk device of FIG. 11 is not used, the sector address of the new data storage is set even for the sector address of the shadow disk that has been written back, so that it is in the operating state. Therefore, the actual stored data will be entered.

On the other hand, in step S3, when the number of mounted disk devices reaches the maximum configuration of N = 5, the process proceeds to step S7, the address translation table is deleted, and in step S8, the use mode of the spare disk device is used. Check whether or not. If the mode does not use the spare disk device,
In step S5, the parity is written back from the shadow disk device to the additional disk device and the zero data after the writing back is stored in the same manner as before.

On the other hand, if the spare disk device is in the use mode, the spare device controller 30 is started in step S9. In the operating state after starting the backup device control unit 30, if a failure occurs in any of the four disk devices 1 to 4 used for data storage, the backup device control unit 30 causes a failure. Data of the remaining three disk units excluding the disk unit and the data of the failed disk unit from the parity are stored in the spare disk unit 5
After the restoration is completed, a disk array is constructed by the spare disk device 5 and three normal disk devices to meet the request from the host computer 10.

Then, the failed disk device can be used by replacing and repairing it, and then the data of the spare disk device 5 may be transferred, or the newly replaced disk device is logically set as the spare disk device. You may.
In addition to the magnetic disk device, the disk device constituting the disk array 14 can use an appropriate physical device such as an optical disk device, a floppy disk device, or a semiconductor memory device. Also, the above embodiment has the maximum configuration N
= 5 units are taken as an example, but it is needless to say that the maximum number of units can be appropriately set if necessary.

[0052]

As described above, according to the present invention, the number of disk devices having the maximum configuration is arbitrarily determined to be N, so that from the minimum configuration of 3 units to the maximum configuration of N units. , It is possible to add more disk units as needed, and it is not necessary to save the data and parity of the installed disk unit to another disk unit when adding this disk unit. With just this, you can move to the expanded expansion configuration, and the expansion process can be automatically performed by the program sequence of the setup process after the mounting is completed.
It is possible to easily and efficiently add a disk array device.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a block diagram showing an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a logical address map, a virtual address map, and a physical address map according to an embodiment when a spare disk device is not used in the maximum configuration.

FIG. 4 is an explanatory diagram of initialization of the additional disk device and write back of parity when the disk device is added in FIG.

FIG. 5 is an explanatory diagram of initialization of the shadow disk device after parity write-back subsequent to FIG. 4;

FIG. 6 is an explanatory diagram of a physical address map in operation after the completion of expansion for FIG.

FIG. 7 is an explanatory diagram of a logical address map, a virtual address map, and a physical address map according to an embodiment when a spare disk device is used in the maximum configuration.

FIG. 8 is an explanatory diagram of initialization of the additional disk device and write back of parity when the disk device is added in FIG.

FIG. 9 is an explanatory diagram of initialization of the shadow disk device after parity write-back subsequent to FIG. 8;

FIG. 10 is an explanatory diagram of a physical address map in operation after the completion of expansion for FIG.

FIG. 11 is an explanatory diagram of a logical address map, a virtual address map, and a physical address map according to a modified embodiment when the spare disk device is not used in the maximum configuration.

12 is an explanatory diagram of initialization of the additional disk device and write back of parity when the disk device is added in FIG.

FIG. 13 is an explanatory diagram of initialization of the shadow disk device after parity write-back subsequent to FIG. 12;

FIG. 14 is an explanatory diagram of a physical address map in operation after the addition is completed with respect to FIG. 11.

FIG. 15 is a flowchart of a setup process for creating a virtual address map table and an address translation table according to the present invention.

FIG. 16 is a flowchart of a data writing process of the present invention.

FIG. 17 is a flowchart of extension processing of the present invention.

FIG. 18 is a block diagram of a conventional disk array device.

FIG. 19 is an explanatory diagram of expansion in rank units.

FIG. 20 is an explanatory diagram of expansion of a disk device unit.

FIG. 21 is an explanatory diagram of data and parity storage states of a conventional device that does not require saving of existing data and parity.

[Explanation of symbols]

 1 to 6: Disk device 10: Host computer (upper device) 12: Disk array control device 14: Disk array 16: MPU 18: Host interface control unit 20: Device interface control unit 22: Data transfer control unit 24: Virtual address map Table 26: Address conversion table 28: Parity calculation unit 30: Standby device control unit 32: Host interface cable 34: Device interface cable

Claims (6)

[Claims] 1. An expanded configuration method of a disk array device in which N disk devices are connected in parallel to a disk array control device in a maximum configuration, and data is provided in correspondence with the maximum configuration with N disk devices. And a virtual address map table defining addresses for storing the parity is created in advance, and the initial configuration is configured to be expandable by M disk devices in a range of less than the maximum configuration number N and 3 or more. In the configuration state with one disk device,
The storage addresses of data and parity for (M-1) disk devices are the same as those in the virtual address map table, the remaining one disk device is defined as a shadow disk device, and the virtual address map is defined in the shadow disk device. The disk device in the table creates an address conversion table that allocates a storage address for parity that does not actually exist, and reads or writes data and updates the parity by referring to the address conversion table in response to an input / output request from a host device. An extended configuration method of a disk array device characterized by the above. 2. The expansion configuration method for a disk array device according to claim 1, wherein the M disk devices are (M +
1) When the number of disks is increased to one, the storage address corresponding to the virtual address map table of the added disk device is initialized, the parity of the shadow disk device is written back to the additional disk device according to the virtual address map table, and the write is performed. The storage address of the shadow disk device after returning is initialized, the address conversion table is changed in accordance with the expanded configuration of (M + 1) disk devices, and the address conversion is changed after the input / output request from the host device. An extended configuration method for a disk array device, wherein data read or data write and parity update of (M + 1) disk devices are performed with reference to a table. 3. The expansion configuration method for a disk array device according to claim 1, wherein the virtual address map table is set as a spare disk with one disk device being in an empty state at the time of maximum configuration using N disk devices. An extended configuration method for a disk array device, which is created so as to be used as a device. 4. The expansion configuration method for a disk array device according to claim 1, wherein the virtual address map table is set such that all the disk devices are made valid at the time of maximum configuration using N disk devices. An extended configuration method for a disk array device, which is characterized in that it is created so as not to be used. 5. The expansion configuration method for a disk array device according to claim 1, wherein the virtual address map table stores data and parity in (N-1) disk devices, and the remaining one disk is used. A parity control method characterized by being created so that only data is stored in the device. 6. The expansion configuration method for a disk array device according to claim 1, wherein when the number of disk devices reaches a maximum configuration of N units due to expansion, the address conversion table is deleted and input from the host device. An extended configuration method for a disk array device, wherein data read or data write and parity update of the disk device are performed in response to an output request according to the virtual address map table.