# US 2020/0401348 A1 · Storage system and history information management method

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2020/0401348 A1
- Document ID: US20200401348A1
- Status: Published application
- Kind: A1
- Application number: 16/807,317
- Filed: 2020-03-03
- Published: 2020-12-24
- Earliest claimed: 2019-06-18
- Assignees: Hitachi, Ltd.
- Applicants: Hitachi, Ltd.
- Inventors: Ai Satoyama; Tomohiro Kawaguchi; Takaki Matsushita
- Web page: https://patentgrep.com/patent/US20200401348A1

## CPC

- G06F 3/0659: {Command handling arrangements, e.g. command buffers, queues, command scheduling}
- G06F 11/1471: involving logging of persistent data for recovery
- G06F 3/0614: {Improving the reliability of storage systems}
- G06F 3/0619: {in relation to data integrity, e.g. data losses, bit errors}
- G06F 3/0631: {by allocating resources to storage systems}
- G06F 3/065: {Replication mechanisms}
- G06F 3/0653: {Monitoring storage devices or systems}
- G06F 3/0658: {Controller construction arrangements}
- G06F 3/0665: {at area level, e.g. provisioning of virtual or logical volumes}
- G06F 3/0673: {Single storage device}
- G06F 3/0679: {Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]}
- G06F 11/1451: {by selection of backup contents}
- G06F 2201/84: Using snapshots, i.e. a logical point-in-time copy of the data
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A storage system includes a storage controller, plural volumes each configured by the storage controller, and a pool allocating physical storage areas to logical storage areas of the volumes. The storage controller configures a first group including, among the volumes, a first primary volume to which a first target protection period is set, and a first history information volume storing history information about updating to the first primary volume, and a second group including, thereamong, a second primary volume to which a second target protection period is set, and a second history information volume storing history information about updating to the second primary volume. The volumes included in the first and second groups utilize the same physical storage area of the pool. When increasing a free capacity thereof, history information to be purged is determined from the first and second protectable periods such that their protectable periods become the same.

## Claims

### Claim 1

A storage system, comprising:
a storage controller;
a plurality of volumes each comprised of the storage controller; and
a pool configured to allocate physical storage areas to logical storage areas of the volumes,
wherein the storage controller includes:
a first group including, among the volumes, at least one first primary volume to which a first target protection period is set, a first copying volume storing a copy of the first primary volume at a predetermined time, and a first history information volume storing history information about updating to the first primary volume, and
a second group including, among the volumes, at least one second primary volume to which a second target protection period is set, a second copying volume storing a copy of the second primary volume at a predetermined time, and a second history information volume storing history information about updating to the second primary volume,
wherein the volumes included in the first group and the second group utilize the same physical storage area of the pool, and
wherein when a free capacity of the pool is increased from a state in which the history information about the updating to the first primary volume, which is stored in the first history information volume is capable of providing the first target protection period and a first protectable period, and the history information about the updating to the second primary volume, which is stored in the second history information volume is capable of providing a second protectable period equivalent to a period longer than the second target protection period, history information to be purged is determined from the first protectable period and the second protectable period in such a manner that the first protectable period and the second protectable period are put in a predetermined relation.

### Claim 2 (depends on 1)

The storage system according to claim 1, wherein the predetermined relation is that the first protectable period and the second protectable period become the same.

### Claim 3 (depends on 1)

The storage system according to claim 1, wherein the history information to be purged is reflected on the first copying volume and the second copying volume respectively.

### Claim 4 (depends on 1)

The storage system according to claim 1, wherein the storage controller controls the first protectable period and the second protectable period shortened by purging the history information to be purged to be displayed.

### Claim 5 (depends on 1)

The storage system according to claim 1, wherein a part of the history information about the updating to the first primary volume which is stored in the first history information volume configuring the first target protection period, and a part of the history information about the updating to the second primary volume, which is stored in the second history information volume configuring the second target protection period are purged so as to increase a free capacity of the pool, history information to be purged is determined in such a manner that periods during which the first target protection period and the second target protection period are shortened become the same.

### Claim 6 (depends on 5)

The storage system according to claim 5, wherein the storage controller controls the first target protection period and the second target protection period shortened by purging the history information to be purged to be displayed.

### Claim 7 (depends on 6)

The storage system according to claim 6, wherein the storage controller executes purge processing of the history information to be purged in response to the input of a signal to approve the shortening of the displayed target protection periods.

### Claim 8 (depends on 1)

The storage system according to claim 1, wherein the storage controller includes:
the first group comprised of, among the volumes, a first snapshot volume storing a first generation snapshot of the first primary volume to which the first target protection period is set, and a second snapshot volume storing a first generation snapshot of the second primary volume to which the second target protection period is set, and
the second group comprised of, among the volumes, a third snapshot volume storing a second generation snapshot of the first primary volume to which the second target protection period is set, and a fourth snapshot volume storing a second generation snapshot of the second primary volume to which the second target protection period is set.

### Claim 9

A history information management method of a storage system including a storage controller, a plurality of volumes each comprised of the storage controller, and a pool configured to allocate physical storage areas to logical storage areas of the volumes, comprising the steps of:
allowing the storage controller to include a first group including, among the volumes, at least one first primary volume to which a first target protection period is set, a first copying volume storing a copy of the first primary volume at a predetermined time, and a first history information volume storing history information about updating to the first primary volume, and a second group including, among the volumes, at least one second primary volume to which a second target protection period is set, a second copying volume storing a copy of the second primary volume at a predetermined time, and a second history information volume storing history information about updating to the second primary volume;
allowing the volumes included in the first group and the second group to utilize the same physical storage area of the pool; and
when a free capacity of the pool is increased from a state in which the history information about the updating to the first primary volume, which is stored in the first history information volume is capable of providing the first target protection period and a first protectable period, and the history information about the updating to the second primary volume, which is stored in the second history information volume is capable of providing a second protectable period equivalent to a period longer than the second target protection period, determining the history information to be purged from the first protectable period and the second protectable period in such a manner that the first protectable period and the second protectable period are put in a predetermined relation.