Storage system and storage control method

Patent metadata

Field	Value
Publication number	US-2017075615-A1
Application number	US-201415122770-A
Country	US
Kind code	A1
Filing date	Mar 26, 2014
Priority date	Mar 26, 2014
Publication date	Mar 16, 2017
Grant date	—

Abstract

A second virtual volume having a plurality of second virtual areas is a clone of a first virtual volume having a plurality of first virtual areas. A first real area is allocated from a pool of real areas and based on storage devices to the first virtual volume. A storage controller allocates a second real area to the second virtual area before a write occurs in the second virtual area corresponding to the first virtual area to which the first real area is allocated. A physical area is allocated to a logical area corresponding to the first real area in each storage device, and data based on user data stored in the first real area is stored in the physical area. Each storage device allocates the physical area allocated to the logical area corresponding to the first real area to a logical area corresponding to the second real area.

First claim

1 . A storage system comprising:
a storage device group configured with one or more storage devices; and a storage controller configured to manage a pool configured with a plurality of real areas and based on the storage device group, and a first virtual volume configured with a plurality of first virtual areas and to which a first real area is allocated, and to manage a second virtual volume configured with a plurality of second virtual areas as a clone of the first virtual volume, wherein each of the one or more storage device includes
a storage medium configured with a plurality of physical areas, and
a medium controller coupled to the storage medium, and configured to provide a logical space configured with a plurality of logical areas and to allocate a physical area to a logical area of a write destination,
wherein each real area corresponds to one or more logical areas respectively provided by the one or more storage devices, wherein one or more data based on user data stored in the first real area are respectively stored in one or more physical areas respectively allocated to one or more logical areas corresponding to the first real area, wherein the storage controller is configured to allocate a second real area to the second virtual area before write occurs in the second virtual area corresponding to the first virtual area to which the first real area is allocated, and wherein the medium controller of each of the storage devices is configured to allocate the physical area allocated to the logical area corresponding to the first real area to a logical area corresponding to the second real area.

2 . The storage system according to claim 1 ,
wherein the storage device group is a RAID group configured with a plurality of storage devices, wherein, there is a plurality of stripe groups, each stripe group extending over the plurality of storage devices of the storage device group, wherein each of the real pages corresponds to a stripe group, and wherein the second real area is a real area corresponding to a stripe group having a parity stored in a storage device that is the same storage device in which a parity of user data stored in a stripe group corresponding to the first real area is stored.

3 . The storage system according to claim 2 ,
wherein the storage controller is configured to manage, for each stripe group, a storage device in which a parity is stored, wherein the storage controller is configured to search for an unused stripe group having a parity stored in the storage device that is the same storage device in which a parity of user data stored in a stripe group corresponding to the first real area is stored, and wherein a real area corresponding to the stripe group found by the search is the second real area.

4 . The storage system according to claim 1 ,
wherein the storage controller is configured to transmit one or more copy commands to each of the storage devices, wherein each of the copy commands includes a copy source address that is an address of the logical area corresponding to the first real area, and a copy destination address that is an address of the logical area corresponding to the second real area, and wherein the medium controller of each of the storage devices is configured to receive the copy command, and allocate a physical area allocated to the logical area to which the copy source address specified by the received copy command belongs to the logical area to which the copy destination address belongs, according to the received copy command.

5 . The storage system according to claim 1 ,
wherein the storage controller is configured to receive a write request that specifies the second virtual volume from a host computer, wherein the storage controller is configured to manage an access load of each second virtual area, wherein the storage controller is configured to determine whether there is a low-access load area that is the second virtual area having the access load being a predetermined load or less, and wherein the storage controller is configured to release the second real area from the low-access load area, and allocate the first real area to the low-access load area when there is the low-access load area, and the second real area is allocated to the low-access load area.

6 . The storage system according to claim 5 ,
wherein the storage controller further is configured to transmit a release command that specifies an address of the logical area corresponding to the second real area to the each of the storage devices when there is the low-access load area, and the second real area is allocated to the low-access load area, and wherein the medium controller of each of the storage devices is configured to receive the release command, and release a physical area from the logical area to which the address specified by the release command belongs, according to the release command.

7 . The storage system according to claim 5 ,
wherein the storage controller includes a first memory that is a cache memory, and wherein, when a real area allocated to the second virtual area of a write destination according to the received write request is the first real area, the storage controller is configured to read user data from the first real area to the first memory, update the read user data using write target data according to the received write request, and allocate a third real area to the second virtual area of the write destination as a write destination of the updated user data, in place of the first real area.

8 . The storage system according to claim 7 ,
wherein the storage controller is configured to transmit a write command that specifies an address of the logical area corresponding to the second real area to each of the storage devices when a real area allocated to the second virtual area of the write destination according to the received write request is the second real area, wherein the medium controller of each of the storage devices includes a second memory, and wherein, when having received the write command that specifies an address of the logical area to which a physical area is allocated, the medium controller of each of the storage devices is configured to read data from the allocated physical area to the second memory, update the data in the second memory with write target data, and write the updated data in a new physical area allocated to the logical area of the write destination, in place of the allocated physical area.

9 . The storage system according to claim 7 ,
wherein the storage controller is configured to manage the third real area allocated to the second virtual area of the write destination, in place of the first real area, as a snapshot real area, and manages the second virtual area of the write destination as a snapshot virtual area that is a second virtual area to which the snapshot real area is allocated, and wherein the storage controller is configured not to release the third real area from the low-access load area when the low-access load area is the snapshot virtual area.

10 . The storage system according to claim 9 ,
wherein the storage controller is configured to divide a real area used as the snapshot real area into a plurality of sub real areas, and manage the plurality of sub real areas, and wherein, when the second virtual area of the write destination according to the received write request is a second virtual area to which the plurality of sub real areas is allocated, the storage controller is configured to allocate a free sub real area to a sub real area corresponding to an update portion, of the plurality of sub real areas allocated to the second virtual area of the write destination.

Assignees

• Hitachi Ltd

Inventors

• Imazaki Miho
• Simozono Norio
• Ogawa Junji
• Yoshihara Tomohiro
• Yamamoto Akira
• Akutsu Hiroaki

Classifications

• G06F11/108 Primary

  Parity data distribution in semiconductor storages, e.g. in SSD · CPC title

• G06F3/0665

  at area level, e.g. provisioning of virtual or logical volumes · CPC title

• G06F3/0683

  Plurality of storage devices · CPC title

• G06F3/0631 Primary

  by allocating resources to storage systems · CPC title

• G06F3/0604

  Improving or facilitating administration, e.g. storage management · CPC title