NAS system and remote copy method
AssigneeHitachi, Ltd.
InventorsSadahiro Nakamura, Yasuo Yamasaki
Life of this patent
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Abstract
The present invention remote copies difference data for snapshots in an appropriate manner. A NAS system having one or more file systems for storing data, a snapshot producing section for producing snapshots for the file systems based on a pre-scheduled snapshot acquisition time, a remote copy section for remote copying difference data for the snapshots based on pre-scheduled remote copy start times, and a scheduling section for re-scheduling the time of one or more of an Nth snapshot acquisition time, an Nth remote copy start time, and an (N+1)th remote copy start time, in such a manner that remote copying starting at the Nth remote copy start time finishes by the (N+1)th remote copy start time.
Claims13
A NAS system comprising:
- one or more file systems for storing data;
- a snapshot producing section for producing snapshots for the file systems based on a pre-scheduled snapshot acquisition time;
- a remote copy section for remote copying difference data for the snapshots based on pre-scheduled remote copy start times;
- and
- a scheduling section for re-scheduling the time of one or more of an Nth snapshot acquisition time, an Nth remote copy start time, and an (N+1)th remote copy start time, in such a manner that remote copying starting at the Nth remote copy start time finishes by the (N+1)th remote copy start time.
A remote copy method comprising:
- estimating an amount of difference data for a snapshot of the file system acquired the Nth time based on the amount of difference data for a snapshot of the file system acquired the (N−1)th time;
- and
- re-scheduling the time of one or more of an Nth snapshot acquisition time, an Nth remote copy start time, and an (N+1)th remote copy start time based on an estimated value for the difference data, in such a manner that remote copying starting at the Nth remote copy start time finishes by the (N+1)th remote copy start time.
Dependencies are inferred from the claim text.