Patent ID: 11861205
Assignee: HITACHI, LTD.
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 1:
2. A distributed storage system, comprising:
a storage unit including one or more physical storage devices; and
a plurality of computers accessibly connected via a communication network to each of the one or more physical storage devices in the storage unit,
wherein, for each of the plurality of computers,
the computer performs input/output (I/O) of data to/from an owner volume, the ownership of which is owned by a first computer,
the computer writes data, the data being written into a volume region as a write destination of the owner volume of the computer, into a storage region allocated to the volume region as the write destination in a physical storage region provided by the one or more physical storage devices,
the computer has domain mapping data indicating a relationship between a volume region in the owner volume of the computer and a storage region in the physical storage region and being metadata for that owner volume,
when the owner volume of the computer is a migration object, the computer migrates the ownership of the volume to a second computer as a destination,
an owner volume of a third computer is a storage owner volume,
the storage owner volume is an owner volume to which a storage function is applied, the storage function is to obtain control data related to data I/O, the control data being metadata other than the domain mapping data, in place of or in addition to the domain mapping data,
when the third computer identifies that a volume as a migration object from the third computer to a fourth computer is the storage owner volume, the third computer copies the control data of the storage owner volume to the fourth computer,
the physical storage devices have different I/O performances,
the storage owner volume of the third computer is an auto tiering owner volume being an owner volume to which an auto tiering function is applied,
the auto tiering function is a storage function performing auto tiering of changing a physical storage device as a location destination of data written into a volume region in the storage owner volume according to I/O frequency of the volume region at regular intervals or every time a predetermined event occurs,
the third computer has I/O statistical data as control data indicating a correspondence relationship between the volume region and the I/O frequency for the auto tiering owner volume,
when the third computer identifies that the volume as the migration object from the third computer to the fourth computer is the auto tiering owner volume, the third computer copies, to the fourth computer, a domain mapping data of the auto tiering owner volume and the I/O statistical data for the auto tiering owner volume, and
after the auto tiering owner volume is migrated to the fourth computer, the fourth computer updates the copied I/O statistical data according to I/O to/from the auto tiering owner volume, and performs auto tiering for the auto tiering owner volume based on the I/O statistical data.