JP2016091164A - Disk control apparatus, disk control method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk control apparatus configured to allow various storage devices to be added when a logical disk is reconfigured by adding a new storage device.SOLUTION: A disk control apparatus is connected to a plurality of storage devices each including a plurality of partitions, configures a virtual RAID logical disk based on RAID, by use of some of the partitions included in the storage devices as components, and reconfigures a RAID logical disk by using at least one partition included in an added storage device and plural partitions constituting the RAID logical disk, or partitions not constituting the RAID logical disk, as components. The added device has memory capacity smaller than that of a storage device having the smallest memory capacity of the storage devices.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a disk control apparatus, a disk control method, and a program for constructing a logical disk (RAID logical disk) using a plurality of storage devices by using a RAID (Redundant Array of Inexpensive Disks) technique.

  A RAID technology for constructing a logical disk using a plurality of storage devices is known. There is also a technique for reconstructing a new logical disk including an added storage device by adding a new storage device to a storage device group in which a logical disk has already been constructed by RAID. For example, see Patent Document 1).

US Patent Application Publication No. 2004/073747

  In the conventional RAID technology, when a logical disk is first constructed, the storage capacity of the logical disk is determined based on the storage device having the smallest capacity among the plurality of storage devices. Therefore, when a new storage device is added, it is limited to add a storage device having a smaller capacity than the storage device having the minimum capacity in the existing storage device group.

  The present invention has been made in view of the above circumstances, and when a new storage device is added and a logical disk is reconstructed, a disk control device, a disk control method, and a disk control device capable of adding various storage devices, And providing a program is one of its purposes.

  A disk control device according to an aspect of the present invention is connected to a plurality of storage devices each including a plurality of partitions, and includes a part of the plurality of partitions included in the plurality of storage devices as a component. A construction means for constructing at least one virtual RAID logical disk based on the above, and when a new storage device is added as an additional device, at least one partition included in the additional device, and the plurality of storage devices Disk control including: a plurality of partitions included in the RAID logical disk, or a partition that does not configure the RAID logical disk, and a reconstructing unit that reconstructs the RAID logical disk A device, Serial additional device is characterized in that the storage capacity than the smallest storage device storage capacity among the plurality of storage devices is small.

  In the disk control device, the construction unit may divide each of the plurality of storage devices into partitions having a predetermined unit capacity, and the additional device may have a storage capacity larger than the unit capacity. Good.

  Further, in the disk control device, the construction unit acquires information on the performance of the storage device from each of the plurality of storage devices, and uses the information on the acquired performance to configure the components of the RAID logical disk. A storage device including a candidate partition may be selected.

  Further, in the disk control device, the construction unit selects, for each of the plurality of storage devices, a partition constituting the RAID logical disk using information on a position occupied by each of the plurality of partitions in the storage device. It is good as well.

  In addition, prior to the construction of the RAID logical disk, the disk controller arranges information on the storage capacity that can be used by the user when the RAID logical disk is constructed for each number of storage devices that are allowed to fail. It is good also as including the means to present to.

  Further, in the disk control method according to one aspect of the present invention, for a plurality of storage devices each including a plurality of partitions, a part of the plurality of partitions included in the plurality of storage devices is used as a component. , A construction step of constructing at least one virtual RAID logical disk based on RAID, and, when a new storage device is added as an additional device, at least one partition included in the additional device, and the plurality of storages A rebuilding step in which a RAID logical disk is newly reconstructed using a plurality of partitions constituting the RAID logical disk or a partition not constituting the RAID logical disk among the plurality of partitions included in the device; and Including Device is characterized in that the storage capacity than the smallest storage device storage capacity among the plurality of storage devices is small.

  Further, a program according to one embodiment of the present invention includes a computer connected to a plurality of storage devices each including a plurality of partitions, and a part of the plurality of partitions included in the plurality of storage devices as components. As a construction means for constructing at least one virtual RAID logical disk based on RAID, and when a new storage device is added as an additional device, at least one partition included in the additional device, and the plurality Reconstructing means for newly reconstructing a RAID logical disk using a plurality of partitions constituting the RAID logical disk or a partition not constituting the RAID logical disk among a plurality of partitions included in the storage device , As machine A program for causing, the additional device is characterized in that the storage capacity than the smallest storage device storage capacity among the plurality of storage devices is small. This program may be stored in a computer-readable information storage medium.

  According to the present invention, when reconstructing a logical disk by adding a new storage device, it is possible to add a storage device having a limited storage capacity.

1 is an overall schematic diagram of a disk system including a disk control device according to an embodiment of the present invention. It is a functional block diagram of the disk control apparatus which concerns on embodiment of this invention. It is a figure which shows an example of a structure of a logical disk. FIG. 4 is a diagram illustrating an example of a configuration of a logical disk when an additional hard disk is added to the configuration illustrated in FIG. 3. It is a figure which shows an example of the screen for accepting selection of the hard disk used for construction of a logical disk. It is a figure which shows an example of the screen for accepting selection of failure tolerance number. It is a figure which shows an example of a structure of the logical disk in a modification. It is a figure which shows an example of a structure of a logical disk when an additional hard disk is added with respect to the structure shown in FIG.

  The disk control apparatus 1 according to an embodiment of the present invention controls a plurality of storage devices and constructs a logical disk (RAID logical disk) based on RAID technology. A RAID logical disk is a virtual information storage medium that stores data to be read and written by a computer, and is constructed by a plurality of storage devices. Hereinafter, a RAID logical disk constructed by the disk controller 1 according to the present embodiment is simply referred to as a logical disk.

  The disk control apparatus 1 according to the present embodiment, as a rule, constructs one logical disk across a plurality of storage devices in order to ensure data redundancy. More specifically, it is assumed that the disk control device 1 constructs a logical disk at any RAID level of RAID1, RAID5, and RAID6. In RAID1, a logical disk is constructed with two storage devices as components, and the same data is written to each of the two storage devices (mirroring). Thereby, even when a failure occurs in one storage device, the processing can be continued using the data recorded in the other storage device.

  In RAID5, a logical disk is constructed with three or more storage devices as components. The data to be written is divided into blocks and distributedly recorded in three or more storage devices in units of blocks. Further, when data of each block is recorded, parity is generated based on the data, and one of the storage devices constituting RAID 5 has parity, and the remaining storage devices have data in the block. Distributed recording. As a result, even if one of the storage devices constituting RAID 5 fails, the original data can be restored using the data and parity recorded in the remaining storage device.

  In RAID 6, a logical disk is constructed with four or more storage devices as components. In the case of RAID 6, two types of parity are generated in block units for the data to be written, the parity is recorded in two storage devices of the storage devices constituting RAID 6, and the original data is stored in other storage devices. Distributed recording. Therefore, according to the RAID 6 system, unlike the case of RAID 1 and RAID 5, even when a failure occurs in two storage devices, the original data is restored from the data and parity recorded in the remaining storage devices. Can do.

  FIG. 1 is an overall schematic diagram of a disk system including a disk controller 1 according to the present embodiment. The disk system includes a disk control device 1, a plurality of hard disks 2 connected to the disk control device 1, and a client device 3 that accesses the hard disk 2 via the disk control device 1. ing. With this disk system, the user of the client apparatus 3 can read / write data from / to the logical disk constructed by the disk control apparatus 1.

  As shown in FIG. 1, the disk control device 1 includes a control unit 11, a memory 12, an I / O unit 13, and a communication unit 14. In the present embodiment, the disk controller 1 is connected to a plurality of hard disks 2 that are physical storage devices, and a logical disk is constructed using these hard disks 2. Further, it is assumed that the disk control device 1 is a NAS (Network Attached Storage) or the like and is connected to the client device 3 via a communication network such as a LAN. The client device 3 may be various information processing devices that can access the disk control device 1 via a LAN, such as a personal computer or a smartphone. In the present embodiment, the client device 3 writes data to and reads data from the logical disk constructed by the disk control device 1.

  The control unit 11 is a CPU or the like, and performs various types of information processing according to programs stored in the memory 12. The memory 12 is a RAM, a nonvolatile memory, or the like, and stores a program executed by the control unit 11.

  The I / O unit 13 is an interface for accessing the hard disk 2 and may correspond to various standards such as SCSI, IDE, and SATA. The disk control device 1 may be configured to store the hard disk 2 inside the casing, or may be connected to the hard disk 2 outside the casing so that data communication is possible. In either case, the disk control device 1 writes and reads data to and from each hard disk 2 via the I / O unit 13.

  The communication unit 14 is an interface for data communication with an external computer, and may be a LAN card or the like when the disk control device 1 is NAS. The disk control device 1 receives an access request to the logical disk from the client device 3 via the communication unit 14.

  Hereinafter, functions realized by the disk control device 1 will be described. As shown in FIG. 2, the disk controller 1 functionally includes a logical disk construction unit 21, a reconstruction unit 22, a disk access unit 23, a logical disk control unit 24, and a user interface unit 25. It is configured to include. These functions are realized when the control unit 11 executes a program stored in the memory 12. This program may be stored in the memory 12 from the time of shipment of the disk controller 1 from the factory, or may be provided to the disk controller 1 via a communication line such as the Internet. Further, the information may be stored in a computer-readable information storage medium such as an optical disk and provided to the disk control device 1.

  The logical disk constructing unit 21 constructs an initial logical disk for a plurality of hard disks 2 in a state where the logical disk is not yet constructed at a timing such as when the use of the disk control device 1 is started. . At this time, the logical disk construction unit 21 divides the storage area of each hard disk 2 into a plurality of partitions, and constructs a plurality of logical disks in units of the partitions. That is, each logical disk is constructed by using some partitions among the plurality of partitions included in the plurality of hard disks 2 as a constituent element.

  Furthermore, in the present embodiment, the logical disk construction unit 21 divides each hard disk 2 into partitions having a predetermined unit capacity. As a result, the storage capacity of each partition all matches the unit capacity.

  As a specific example, a hard disk 2A having a storage capacity of 1.5 TB, a hard disk 2B having a storage capacity of 2 TB, and a hard disk 2C having a storage capacity of 3 TB are connected to the disk controller 1, and the unit capacity is set to 1 TB. This case will be described with reference to FIG. In this case, the logical disk construction unit 21 includes the partition A1 in the hard disk 2A, the two partitions B1 and B2 in the hard disk 2B, and the three partitions C1, partition C2, and partition C3 in the hard disk 2C. Reserve each partition. All of these six partitions have a storage capacity of 1 TB. As indicated by the hatched portion in the figure, in this example, the hard disk 2A has a storage capacity of 0.5 TB, but this storage capacity is less than 1 TB and a partition for the unit capacity is secured. I can't. Therefore, 0.5 TB becomes a free area where data cannot be written, and is excluded from the management target of the RAID function.

  In this example, the logical disk construction unit 21 constructs a RAID 5 logical disk L1 using the partition A1, the partition B1, and the partition C1 as components. Further, the logical disk L2 of RAID1 is constructed with the partition B2 and the partition C2 as components.

  Here, the partition C3 becomes a surplus partition and is not used for construction of a logical disk. However, the partition C3 may form a logical disk together with the new hard disk 2 when the new hard disk 2 is connected to the disk controller 1 later. Therefore, the logical disk building unit 21 sets this partition C3 as a reserved area for expansion used for building a RAID 1 logical disk in the future and manages it together with other partitions used for building the logical disk. And As a result, direct access to the partition C3 from the outside of the disk control apparatus 1 can be restricted so that data is not stored in a partition for which redundancy is not ensured. In the following, the state of the reserved area for RAID1 construction is denoted as “R1-”. If only one hard disk 2 is connected to the disk controller 1, if all partitions in this hard disk 2 are set as reserved areas where access is restricted, a new hard disk 2 is added and redundant. Until data can be secured, no data can be written. Therefore, when only one hard disk 2 is still connected to the disk controller 1, the logical disk construction unit 21 may exceptionally set the R1-partition as a logical disk into which data can be written.

  In this embodiment, before the logical disk construction unit 21 constructs a logical disk, the number of hard disks 2 (hereinafter referred to as allowable failure number) that can restore recorded data even if a failure occurs is determined in advance. To do. The parameter of the allowable number of failures is set to either 1 or 2 based on an instruction from the user. When the allowable number of failures is set to 1, the logical disk construction unit 21 constructs a RAID 1 or RAID 5 logical disk because the data has only to be made redundant so as to withstand up to one failure. At this time, the surplus partition that is not used for constructing the logical disk is managed as R1-. Note that the above-described example of FIG. 3 shows a configuration example when the allowable number of failures is 1. On the other hand, when the allowable number of failures is 2, the logical disk construction unit 21 needs to set the RAID level of the logical disk to be constructed to RAID6. Therefore, a logical disk cannot be constructed while the number of hard disks 2 is less than four, and all the partitions in the hard disk 2 of three or less are managed as reserved areas for RAID 6 construction. .

  The logical disk construction unit 21 does not always use all of the hard disks 2 connected to the disk control device 1 for construction of the logical disk. For example, one of the hard disks 2 may be set as a spare disk in accordance with a user instruction or the like. Here, the spare disk is not used in the construction of the logical disk by the logical disk construction unit 21 among the plurality of hard disks 2 connected to the disk controller 1, and a failure has occurred in the hard disk 2 constituting the logical disk. This is a spare storage device used as an alternative in some cases. Further, the logical disk construction unit 21 may exclude a part of the hard disk 2 connected to the disk controller 1 from being managed without using it as a component of the logical disk or as a spare disk. The hard disk 2 that is not to be managed is accessed from the client device 3 alone. In this case, the logical disk construction unit 21 may select a candidate for the hard disk 2 used for logical disk construction in accordance with a given standard. Specific examples of such candidate selection criteria will be described later.

  When the new hard disk is connected to the disk controller 1 after the logical disk building unit 21 has built the logical disk using the connected hard disk 2, the rebuilding unit 22 receives the new hard disk and performs logical processing. Rebuild the disk. Hereinafter, a hard disk newly connected after the logical disk is constructed by the logical disk construction unit 21 will be referred to as an additional hard disk 2n. The reconstruction unit 22 reconstructs a logical disk that spans these hard disks with the existing hard disk 2 and the additional hard disk 2n as components.

  In the present embodiment, the storage capacity Cn of the additional hard disk 2n that can be used for reconstruction by the reconstruction unit 22 may be smaller than the minimum capacity Cmin of the storage capacity of each existing hard disk 2. However, the storage capacity Cn needs to be larger than at least the minimum capacity of the storage capacity of each partition secured in the existing hard disk 2. In particular, in this embodiment, since all partitions are secured so as to match the unit capacity, the storage capacity Cn of the additional hard disk 2n must be greater than or equal to this unit capacity. When the additional hard disk 2n is newly connected, the reconstruction unit 22 refers to the storage capacity and determines whether or not the additional hard disk 2n can be used for reconstruction. If it is determined that the additional hard disk 2n can be used, the additional hard disk 2n is accepted as a reconstruction target, and a reconstruction process as described in detail below is executed. On the other hand, if it is determined that it cannot be used, the reconstruction process using the additional hard disk 2n is stopped, a screen for setting a new unit capacity value is presented to the user, or a new unit is displayed. Specification of a capacity value may be received from the user.

  As a specific example, when the additional hard disk 2n is added to the configuration shown in FIG. 3, the storage capacity Cn may be smaller than 1.5 TB which is the minimum capacity Cmin of the three hard disks 2, but the unit capacity It needs to be 1 TB or more. If the unit capacity is 1 TB or more, a partition with a unit capacity of 1 TB is secured in the additional hard disk 2n, and that partition and a partition that constitutes one of a plurality of already constructed logical disks, or a partition that does not constitute a logical disk , Can be used to reconstruct the logical disk.

  Here, the rebuilding rule of the logical disk when the rebuilding unit 22 performs the rebuilding will be described.

  First, the reconstruction rule when the allowable number of failures is 1 will be described. When the R1-partition (that is, a partition that does not constitute a logical disk) exists in the existing hard disk 2, the reconstruction unit 22 preferentially selects at least one of the newly reserved partitions in the additional hard disk 2n. A RAID1 logical disk is newly constructed in combination with the R1-partition. As a result, the partition that has not been used for data writing until now can be used as a logical disk.

  If the R1-partition does not exist in the existing hard disk 2 and a RAID 1 logical disk is constructed, the reconstruction unit 22 adds a new hard disk 2n to the two partitions constituting the RAID 1 logical disk. Add a new partition and rebuild the logical disk. At this time, since there are three partitions as the constituent elements of the logical disk, the reconstruction unit 22 extends the RAID 1 logical disk to the RAID 5 logical disk.

  If neither the R1-partition nor the RAID1 logical disk exists in the existing hard disk 2, and the logical disk is constructed with RAID 5, the reconstruction unit 22 configures the RAID 5 logical disk 3 The RAID 5 logical disk is reconstructed by adding the partition of the additional hard disk 2n to the above partitions. At this time, the reconfigured RAID 5 logical disk has one more partition than the pre-reconstructed one, and the storage capacity increases accordingly. When there are a plurality of RAID5 logical disks, the reconstruction unit 22 adds a partition of the additional hard disk 2n and selects a logical disk to be reconstructed according to a given criterion. This given criterion may be, for example, a criterion for preferentially selecting a logical disk having a small number of constituent partitions.

  FIG. 4 shows a configuration example of the logical disk after the rebuilding unit 22 performs rebuilding according to the rebuilding rules described above. Here, as shown in the configuration example of FIG. 3, a logical disk is constructed in advance, and an additional hard disk 2n of 2.5 TB is added thereto. Partitions N1 and N2 each having a unit capacity of 1 TB are secured in the additional hard disk 2n. Then, the partition N1 is combined with the partition C3 of R1-, and the logical disk L3 of RAID1 is newly constructed. On the other hand, the partition N2 is combined with the partitions B2 and C2 constituting the logical disk L2, and the logical disk L2 is reconstructed by these three partitions. As a result, the RAID level of the logical disk L2 is changed from RAID1 to RAID5, and its storage capacity is expanded.

  Next, a logical disk reconstruction rule when the allowable number of failures is 2 will be described. When the allowable number of failures is 2, all the logical disks need to be constructed with RAID 6, and therefore, the partition included in the existing hard disk 2 is not a partition constituting the RAID 6 logical disk or used for the logical disk. It is either a reserved area partition. In this case, if there are already three reserved areas distributed on the three hard disks 2, the reconstruction unit 22 adds a partition in the additional hard disk 2n to these reserved areas, and newly creates a RAID 6 logic. Build the disc. On the other hand, when there is no reserved area where a RAID 6 logical disk can be newly created, the reconstruction unit 22 adds the partition in the additional hard disk 2n to four or more partitions constituting the existing RAID 6 logical disk, Rebuild the RAID 6 logical disk. In this case, as in the case of rebuilding a RAID 5 logical disk, the logical disk to be reconstructed may be selected based on a criterion such as giving priority to a logical disk with a small number of constituent partitions.

  When the disk control device 1 constructs a RAID 5 or RAID 6 logical disk, an upper limit may be set for the number of partitions that are constituent elements thereof. When the additional hard disk 2n is added in a state where the allowable number of failures is 1 and only the RAID 5 logical disk whose number of partitions has reached the upper limit exists, the reconstruction unit 22 changes the partition in the additional hard disk 2n to R1- Set to. Further, when the additional hard disk 2n is added in a state where the allowable number of failures is 2 and only the RAID 6 logical disk whose number of partitions has reached the upper limit exists, the reconstructing unit 22 selects the partition in the additional hard disk 2n. It is set as a reserved area for constructing a RAID 6 logical disk in the future.

  Further, when a plurality of additional hard disks 2n are additionally connected to the disk controller 1 at the same time, for example, the reconstruction unit 22 uses the same determination criteria as when these additional hard disks 2n are sequentially added one by one. Decide which partitions should be combined to rebuild the logical disk. In this case, of the added additional hard disks 2n, which additional hard disk 2n is determined to be added first may be determined according to the storage capacity of each additional hard disk 2n. Specifically, for example, the reconstruction unit 22 determines the order of reconstruction assuming that the additional hard disk 2n having a small storage capacity is added first.

  The disk access unit 23 accesses the logical disk in response to an access request from the client device 3. At this time, the disk access unit 23 specifies the hard disk 2 to be accessed according to which hard disk 2 is actually configured by the logical disk that is the target of the access request, and stores the data corresponding to the content of the access request. Write and read. When writing data to the hard disk 2, the same data is written to different hard disks 2 according to the RAID level of the logical disk, or the parity of the write data is generated in units of blocks, and distributedly recorded on a plurality of hard disks 2. Or As a result, the client device 3 stores data in the logical disk constructed by the logical disk construction unit 21 or does not need to consider the actual configuration of the physical hard disk 2 or the data stored in the logical disk. Can be read.

  The logical disk control unit 24 controls the logical disk constructed by the logical disk construction unit 21 and the reconstruction unit 22. Specifically, when any failure occurs in any of the hard disks 2 connected to the disk control device 1, the logical disk control unit 24 disconnects the hard disk 2 in which the failure has occurred (hereinafter referred to as a failed disk). The remaining hard disk 2 is used to control the process to continue. Here, the failed disk is the hard disk 2 that cannot be normally accessed from the disk control apparatus 1 and is not limited to the hard disk 2 that has physically failed, but the hard disk 2 that is disconnected from the disk control apparatus 1 or the like. May be included.

  Since redundancy is not ensured in the state where there is a failed disk, the user needs to replace the failed disk with a normal hard disk 2. Hereinafter, the hard disk 2 that is replaced with a failed disk and connected to the disk controller 1 is referred to as a replacement disk. Usually, this replacement disk needs to have a storage capacity equal to or greater than the storage capacity of the failed disk. Otherwise, the same partition as the failed disk is secured in the replacement disk, and all the information stored in the failed disk cannot be stored again in the replacement disk. Information to be stored in the replacement disk can be regenerated from data stored in another hard disk 2. Here, when the storage capacity of the replacement disk is larger than the storage capacity of the failed disk by a unit capacity or more, a new partition having a unit capacity can be secured in the replacement disk. This new partition may be used for rebuilding an existing logical disk with the same rebuilding rules as when the additional hard disk 2n is added.

  Further, when a spare disk is connected to the disk control device 1, the logical disk control unit 24 can recover the failure by exchanging the spare disk with a failed disk. While no hard disk 2 is operating normally without any failure, the spare disk is unused, but when any hard disk 2 becomes a failed disk, the logical disk control unit 24 Start using a spare disk instead of the failed disk. Then, the information stored in the failed disk is stored in the spare disk in the same manner as when the replacement disk is added manually.

  In order to make a spare disk function as a replacement for a failed disk when a failure occurs in any of the hard disks 2, the spare disk has a storage capacity of at least the maximum capacity Cmax among all the hard disks 2 used for logical disk construction. It is desirable to provide. Also, when multiple spare disks are connected to the disk controller 1, when a failure occurs in the existing hard disk 2, the failure is given priority to the spare disk with the smallest storage capacity among the multiple spare disks. It shall be used for disk replacement. Thereby, the condition that the storage capacity of the spare disk is equal to or larger than the maximum capacity Cmax of the existing hard disk 2 can be maintained.

  Further, when the additional hard disk 2n is further connected in a state where the spare disk is connected, the rebuilding unit 22 does not use the additional hard disk 2n to reconstruct the logical disk but has been connected so far. The spare disk may be used to reconstruct the logical disk. When an additional hard disk 2n having a larger storage capacity than the connected spare disk is newly connected, if the additional hard disk 2n is used as it is and reconstruction is performed, the spare disk is used for logical disk construction. The condition that the storage capacity is larger than the maximum capacity Cmax of the existing hard disk 2 is not satisfied. Therefore, a spare disk is used for reconstructing a logical disk instead of the additional hard disk 2n, and the additional hard disk 2n is set as a new spare disk, so that the spare disk has a storage capacity equal to or larger than the maximum capacity Cmax of the existing hard disk 2. You can keep the state you have.

  In the above description, it is assumed that the replacement disk or the spare disk needs to have a storage capacity larger than that of the failed disk. However, in this embodiment, the storage capacity of the replacement disk or the spare disk does not necessarily have to be greater than the storage capacity of the failed disk. This is because each hard disk 2 is divided into a plurality of partitions, and a logical disk is constructed in units of partitions. Therefore, for example, when a hard disk 2 including a free area that does not belong to any partition fails, such as the hard disk 2A in FIG. 3, the storage capacity is larger than the partition used for constructing the logical disk in the failed disk. If it is a replacement disk, it can be replaced with the failed disk. Specifically, in the example of FIG. 3, if the replacement disk has a storage capacity of 1 TB or more, the hard disk 2A has a failure even if the storage capacity is less than 1.5 TB of the hard disk 2A. Acts as an alternative when it occurs. Even if the storage capacity of the replacement disk is smaller than the storage capacity of all partitions used for logical disk construction in the failed disk, the replacement disk has a larger storage capacity than some partitions in the failed disk. Can partially serve as a replacement for a failed disk. For example, in the example of FIG. 3, when a failure occurs in the hard disk 2B, if a replacement disk having a storage capacity of 1 TB or more but less than 2 TB is connected, all partitions of the failed disk cannot be replaced. The replacement disk can be used as an alternative to the other partition (eg, partition B1). Similarly, even if the spare disk does not necessarily have a storage capacity equal to or greater than the maximum capacity Cmax of the connected hard disk 2, it can be replaced with a failed disk to replace a part or all of its functions.

  The user interface unit 25 receives an instruction necessary for constructing and controlling the logical disk from the user, and sends the contents of the instruction to each of the logical disk constructing unit 21, the rebuilding unit 22, and the logical disk control unit 24. Output. In addition, the user interface unit 25 performs control to display a management screen for accepting an instruction from the user and providing the user with various information regarding the logical disk to be constructed on a display that the user browses.

  Specifically, for example, the user interface unit 25 may be realized by a web application program. In this case, a user who uses the client device 3 starts a web browser program on the client device 3 and accesses the disk control device 1 via the web browser program. Thereby, a management screen showing information provided by the user interface unit 25 can be browsed on a display connected to the client device 3. Alternatively, the user may access the disk control device 1 by starting a management program for the disk control device 1 on the client device 3. Also in this case, information related to the state of the hard disk 2 and the configuration of the logical disk is displayed on the display connected to the client device 3 based on the control of the user interface unit 25. Some specific examples of screens presented to the user by the user interface unit 25 will be described in detail later.

  Here, a specific example in which the logical disk construction unit 21 selects a candidate for the hard disk 2 used for construction of the logical disk will be described. As described above, the logical disk construction unit 21 does not necessarily use all the hard disks 2 connected to the disk control device 1 for construction of the logical disk. Therefore, the logical disk building unit 21 selects a hard disk 2 that is a candidate for use in building a logical disk according to a given standard (that is, a hard disk 2 that includes a partition that is a candidate for a component of the logical disk. You may select from all the connected hard disks 2. The selection criteria in this case will be described in detail below. The selected candidate disk is presented to the user by the user interface unit 25. The user may designate the presented candidate disk as it is to instruct the construction of the logical disk, or select the hard disk 2 that is actually used for constructing the logical disk by referring to the presented candidate disk. May be. Although the user finally determines the hard disk 2 to be used for logical disk construction here, the logical disk construction unit 21 may construct a logical disk using the candidate disk as a target for use as it is.

  Hereinafter, a specific example of selection criteria when the logical disk construction unit 21 selects a candidate disk will be described. In this example, the logical disk construction unit 21 acquires information regarding the performance of the hard disk 2 from each of the hard disks 2 connected to the disk control device 1. Then, a candidate disk is selected using the acquired performance information.

  Information related to the performance includes information on basic specifications of the hard disk 2 such as information on the manufacturer of the hard disk 2 and geometry information. By specifying such information, it is possible to estimate performance such as speed when the hard disk 2 reads and writes data. Further, the performance information may be information such as throughput and seek time that directly indicates the performance of the hard disk 2. Such information includes, for example, S.I. M.M. A. R. T.A. It can be obtained from each hard disk 2 using technology.

  The logical disk construction unit 21 that has acquired information on the performance of each hard disk 2 selects candidate disks so that the average performance of the candidate disks is high or the variation in performance among candidate disks is small. This is because if a hard disk 2 that is larger and inferior in performance than the other hard disks 2 is added to the target of the logical disk construction, the hard disk 2 becomes a bottleneck and the access performance to the logical disk decreases. Therefore, the logical disk construction unit 21 groups the hard disks 2 having relatively close performances and selects them as candidate disks, and excludes the hard disks 2 having a large performance difference from other hard disks 2 from the candidate disks. As a result, when a logical disk is constructed for a candidate disk, the performance of reading / writing data from / to the logical disk can be improved as compared to the case where a logical disk including the hard disk 2 other than the candidate disk is constructed. it can.

  In addition, the logical disk construction unit 21 may determine how to construct a logical disk by combining the partitions in the hard disk 2 determined as the logical disk construction target according to a given standard. . A specific example of the standard in this case is a standard regarding the physical position that each partition occupies in the hard disk 2. This is because the access performance varies depending on the physical position of each partition.

  Specifically, after determining the hard disk 2 as a component of the logical disk to be constructed, the logical disk construction unit 21 determines which partition in the hard disk 2 is to be used as a constituent element of the logical disk. The position is determined using information on the position occupied in the hard disk 2. At this time, it is desirable that the logical disk construction unit 21 determines a partition to be used for construction of the logical disk so that the performances of the partitions constituting the same logical disk are close to each other. In general, the reading / writing speed of data in one hard disk 2 is fast on the outer peripheral side of the disk and decreases as it approaches the center of the disk. Therefore, when the performance of the hard disk 2 itself that is a constituent element is approximately the same, the performance difference between the partitions that configure the same logical disk can be reduced by combining partitions that are secured at positions close to each other. Further, the logical disk construction unit 21 may be used for construction of logical disks in order from the partition closest to the outermost periphery in each hard disk 2. Thereby, it is possible to preferentially use a partition that is estimated to have good access performance.

  As a specific example, when the same hard disk 2 as in the example of FIG. 3 is connected, the hard disk 2B has a partition B1 and a partition B2 in order from the outer periphery, but the hard disk 2C has a partition in order from the inner periphery. Assume that C1, partition C2, and partition C3 are secured, and that partition C3 is located on the outermost periphery. In this case, unlike FIG. 3, the logical disk construction unit 21 constructs logical disks in the combinations described below. That is, the logical disk L1 is constructed with the partition A1, the partition B1, and the partition C3 located on the outermost periphery of each hard disk 2 as components. Then, the logical disk L2 is constructed using the partition B2 and the partition C2 as components, and the partition C1 estimated to have the lowest performance in the hard disk 2C is defined as R1-. Thereby, the performance difference of each partition in the same logical disk can be reduced.

  Hereinafter, a specific example of a screen presented to the user under the control of the user interface unit 25 will be described. Prior to the first logical disk construction, the user interface unit 25 determines how many parameters of the allowable number of failures are set, how much the unit capacity of the partition is, and which hard disk 2 is used for the logical disk. The user may accept the designation of whether or not to construct. Furthermore, when receiving these parameters from the user, information used as a determination material may be presented to the user.

  In particular, how many parameters of the allowable number of failures are set greatly affects the storage capacity available to the user. This is because in order to increase the allowable number of failures, it is necessary to increase the redundancy of the stored data, and the storage capacity of the constructed logical disk is reduced accordingly. Also, which hard disk 2 is used to construct the logical disk naturally affects the storage capacity of the logical disk. Therefore, when accepting selection of the hard disk 2 or parameter setting for the allowable number of failures from the user, it is desirable to present the influence of the setting to the user in an easy-to-understand manner. Therefore, the user interface unit 25 accepts selection of the hard disk 2 used for logical disk construction prior to the construction of the logical disk by the logical disk construction unit 21 and constructs a logical disk using the selected hard disk 2. Display control is performed in which information on storage capacity usable by the user is arranged for each allowable number of failures and presented to the user.

  FIG. 5 is a diagram showing an example of a screen presented to the user by such display control. In the example of this figure, a list of connected hard disks 2 is displayed at the top of the screen, and a check box for selection is provided on the left side of each hard disk 2. The model name and size of each hard disk 2 are also displayed in a list.

  Further, at the bottom of the screen, the storage capacity that can be used when a logical disk is constructed using the selected hard disk 2 is displayed in a graph format so that it can be easily understood intuitively. Specifically, the upper graph shows the storage capacity of the logical disk that can be used when the parameter for the allowable number of failures is set to 1, and the middle graph is used when the parameter for the allowable number of failures is set to 2. The possible storage capacity of the logical disk is shown. Further, “for data protection” in the figure indicates an area (an area for storing mirror data or parity data) used for ensuring redundancy. When the user switches on / off the check box corresponding to each hard disk 2, the contents of these graphs are changed in real time in accordance with this switching. Thus, the user can select the hard disk 2 to be used for constructing the logical disk while confirming the display of the graph. When the user has selected only three hard disks 2 or less, 2 cannot be selected as the allowable number of failures. In this case, the middle graph may be hidden, or a message indicating that four or more hard disks 2 need to be selected may be displayed instead of displaying the usable storage capacity.

  Further, the lower graph shows the storage capacity that can be used when the logical disk is constructed using the candidate disk selected by the logical disk construction unit 21 using the performance-related information as described above. In the example of this figure, it is determined that the performance of the disk A, the disk B, and the disk D is higher than that of the disk C, and these three candidate disks have a recommended configuration when it is desired to prioritize performance. Therefore, the lower graph shows the capacity that can be used when this configuration is adopted in a manner that can be compared with the case where the hard disk 2 selected by the user is used. The “unused area” in the lower graph indicates the storage capacity of the hard disk 2 that is not selected (here, the disk C), and is displayed so as to be distinguishable from the storage capacity for data protection. Further, the disk name (disk 3) of the hard disk 2 that has not been selected as a candidate disk is used so that the user can easily understand why the storage capacity corresponds to the “unused area”. It is displayed at a position corresponding to “area”.

  The lowest storage capacity that can be used for logical disk construction is displayed below the graph. The storage capacity displayed here corresponds to the unit capacity for securing the partition.

  When the user selects the hard disk 2 to be used for constructing the logical disk in the state illustrated in FIG. 5 and presses the “Next” button displayed at the bottom of the screen, the parameter of the allowable number of failures is selected. If it is possible, the user interface unit 25 displays a screen for accepting the selection. FIG. 6 shows an example of this screen. In the example of this figure as well, by displaying a graph similar to that shown in FIG. 5, the information on the storage capacity that can be used when constructing the logical disk is presented to the user side by side by the allowable number of failures. The Thus, the user can select the allowable number of failures while intuitively grasping the storage capacity that can be used when each selection is made.

  According to the disk control apparatus 1 according to the embodiment of the present invention described above, a plurality of partitions are secured in the connected hard disk 2 and a logical disk is constructed using the partitions as constituent elements. Even when an additional hard disk 2n having a smaller storage capacity than that of the hard disk 2 used in the above is added, this additional hard disk 2n can be used for expansion of an existing logical disk.

  The embodiment of the present invention is not limited to the above-described embodiment. In the following, a description will be given of a modified example in which only the additional hard disk 2n having a storage capacity equal to or greater than that of the existing hard disk 2 is restricted to the disk controller 1 unlike the description so far.

  In the disk control device 1 according to the present modification, the storage capacity Cn of the additional hard disk 2n used for reconstruction by the reconstruction unit 22 is stored in each hard disk 2 used for the logical disk construction by the logical disk construction unit 21. It is required that the capacity is not less than the maximum capacity Cmax. By providing such conditions, the storage capacity of the hard disk 2 that can be added is limited, but it is not necessary to secure a partition for each unit capacity, and the storage capacity can be used efficiently.

  As a specific example, the case where three hard disks 2A, 2B, and 2C having storage capacities of 1.5 TB, 2 TB, and 3 TB are connected as in FIG. 3 will be described with reference to FIG. In the disk control apparatus 1 according to this modification, the logical disk construction unit 21 secures only one partition A1 in the hard disk 2A with the minimum capacity. In addition, the hard disks 2B and 2C have 1.5 TB partitions B1 and C1 that are the same as the partition A1, respectively. Then, a RAID 5 logical disk L1 is constructed using these three partitions A1, B1, and C1 as components. Further, the partition B2 is secured by using the 0.5 TB free area remaining on the hard disk 2B, and the partition C2 having the same storage capacity is secured on the hard disk 2C. Then, the logical disk L2 of RAID1 is constructed with the partitions B2 and C2 as components. The free space of 1 TB remaining on the hard disk 2C is managed as the partition C3 of R1-.

  Furthermore, the reconstruction of the logical disk performed by the reconstruction unit 22 when the additional hard disk 2n is connected to the configuration of FIG. 7 will be described with reference to FIG. In this modification, the storage capacity of the additional hard disk 2n must be larger than the storage capacity of each existing hard disk 2, so the additional hard disk 2n needs to be 3 TB or more. In FIG. 8, it is specifically assumed that an additional hard disk 2n of 4 TB is connected. In this example, a 1.5 TB partition N 1, a 0.5 TB partition N 2, and a 1 TB partition N 3 are secured in the additional hard disk 2 n in accordance with the partition configuration of the largest hard disk 2 C among the existing hard disks 2. Is done. Further, the remaining 1 TB of free space is secured as the partition N4 of R1-. The partition N1 is used for expansion of the logical disk L1, and the partition N2 is used for expansion of the logical disk L2. The partition N3 is used for constructing a new RAID1 logical disk L3 together with the partition C3.

  As described above, when the additional hard disk 2n is connected, all the existing logical disks are stored when the storage capacity Cn of the additional hard disk 2n is equal to or larger than the maximum capacity Cmax of the existing hard disks 2. Can be extended.

  Even in this modification, the spare disk connected to the disk controller 1 is required to have a storage capacity equal to or larger than the maximum capacity Cmax of the existing hard disk 2 used for logical disk construction. In addition, when a plurality of spare disks are connected, when a failure occurs in the existing hard disk 2, the spare disk having the smallest storage capacity among the plurality of spare disks is preferentially used as a replacement target. . Further, when the additional hard disk 2n is further connected while the spare disk is connected, if the storage capacity of the spare disk is smaller than the storage capacity of the additional hard disk 2n, the rebuilding unit 22 replaces the additional hard disk 2n with the spare disk. The logical disk is reconstructed by using it, and the additional hard disk 2n is set as a new spare disk. As a result, the storage capacity of the spare disk and the additional hard disk 2n can be kept larger than the maximum capacity Cmax of the existing hard disk 2, and the logical disk can be reconstructed according to the restructuring rules described above.

  In the above description, the storage device connected to the disk control device 1 is the hard disk 2. However, the present invention is not limited to this, and various information storage media such as a solid state drive (SSD) are controlled by the disk. It may be connected to the apparatus 1 and used for logical disk construction by the logical disk construction unit 21. Similarly, when a storage device other than the hard disk 2 is added, the reconstruction unit 22 may also reconstruct the logical disk using the added storage device.

  In the above description, the disk control device 1 is a NAS and is connected to the client device 3 via a communication network such as a LAN. However, the present invention is not limited to this, and each function of the disk control device 1 is personal. It may be realized by a program installed in an information processing apparatus such as a computer. In this case, the client device 3 and the disk control device 1 used by the user do not necessarily need to be separated, and a logical disk is constructed on one computer used by the user, and access to the constructed logical disk is possible. It may be performed. Further, at least a part of each function of the disk control device 1 described above may be realized in hardware by a dedicated IC chip or the like.

  In the above description, the disk controller 1 constructs three types of logical disks, RAID1, RAID5, and RAID6. However, the present invention is not limited to this, and another RAID level logical disk may be constructed.

DESCRIPTION OF SYMBOLS 1 Disk control apparatus, 2 Hard disk, 3 Client apparatus, 11 Control part, 12 Memory, 13 I / O part, 14 Communication part, 21 Logical disk construction part, 22 Reconstruction part, 23 Disk access part, 24 Logical disk control part 25 User interface part.

Claims (7)

Connected to multiple storage devices, each containing multiple partitions,
Construction means for constructing at least one virtual RAID logical disk based on RAID, with some of the partitions included in the plurality of storage devices as components;
When a new storage device is added as an additional device, a plurality of partitions that constitute the RAID logical disk among at least one partition included in the additional device and a plurality of partitions included in the plurality of storage devices Reconstructing means for reconstructing a RAID logical disk using a partition that does not constitute the RAID logical disk as a component;
A disk controller including:
The disk controller according to claim 1, wherein the additional device has a storage capacity smaller than a storage device having the smallest storage capacity among the plurality of storage devices. The disk control device according to claim 1,
The construction means divides each of the plurality of storage devices into partitions of a predetermined unit capacity,
The disk controller according to claim 1, wherein the additional device has a storage capacity larger than the unit capacity. The disk control device according to claim 1 or 2,
The construction means acquires information on the performance of the storage device from each of the plurality of storage devices, and uses the acquired information on the performance to include a partition that is a candidate for a component of a RAID logical disk A disk control device characterized by selecting. The disk control device according to any one of claims 1 to 3,
The construction means, for each of the plurality of storage devices, selects a partition constituting a RAID logical disk using information on positions occupied by the plurality of partitions in the storage device. . The disk control device according to any one of claims 1 to 4,
Prior to the construction of the RAID logical disk, the information processing apparatus further includes means for presenting the storage capacity information usable by the user when the RAID logical disk is constructed, arranged for each number of storage devices that are allowed to fail, to the user. A disk controller characterized by the above. For a plurality of storage devices each including a plurality of partitions, at least one virtual RAID logical disk based on RAID is used, with some of the partitions included in the plurality of storage devices as constituent elements. Construction steps to build,
When a new storage device is added as an additional device, a plurality of partitions that constitute the RAID logical disk among at least one partition included in the additional device and a plurality of partitions included in the plurality of storage devices Or a rebuilding step for newly rebuilding a RAID logical disk using a partition that does not constitute the RAID logical disk as a component;
Including
The disk control method, wherein the additional device has a storage capacity smaller than a storage device having the smallest storage capacity among the plurality of storage devices. Computers connected to multiple storage devices, each containing multiple partitions,
Construction means for constructing at least one virtual RAID logical disk based on RAID, with some partitions of the plurality of partitions included in the plurality of storage devices as components; and
When a new storage device is added as an additional device, a plurality of partitions that constitute the RAID logical disk among at least one partition included in the additional device and a plurality of partitions included in the plurality of storage devices Or a rebuilding means for newly rebuilding a RAID logical disk using a partition that does not constitute the RAID logical disk as a component;
Is a program for functioning as
The additional device has a storage capacity smaller than a storage device having the smallest storage capacity among the plurality of storage devices.

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