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Point-in-time recovery on deduplicated storage

  • US 10,255,137 B1
  • Filed: 12/16/2013
  • Issued: 04/09/2019
  • Est. Priority Date: 12/16/2013
  • Status: Active Grant
First Claim
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1. A method for point-in-time recovery on deduplicated storage, the method comprising:

  • receiving a request to recover data, the request specifying a point-in-time;

    defining data protection windows wherein a first data protection window protects snapshots and journal entries and has a first defined protection time range, a second data protection window has a second defined protection time range, and a third data protection window has a third defined protection time range, wherein each defined protection time range represents a backup granularity designating how long a stored snapshot or journal entry is to be stored in each respective data protection window;

    moving snapshots and journal entries from the first data protection window to the second data protection window, and moving snapshots from the second data protection to the third data protection window as time progresses;

    defining respective policies to each data protection window to delete journal entries from the second data protection window after movement from the first data protection window so that only snapshots are stored in the second and third data protection windows, and to delete certain snapshots from the second data protection window so that only prioritized snapshots are stored in the third data protection window;

    dynamically changing each of the first, second, and third data protection window time ranges based on available space in the deduplicated storage to optimize a retention time for protected snapshots and journal entries of the first data protection window if the available space is large or to optimize a retention time for the prioritized snapshots of the third data protection window if the available space is small;

    identifying a backup snapshot nearest to the point-in-time, wherein the backup snapshot has a defined backup granularity defined by the respective data protection window storing the backup snapshot;

    identifying a journal entry nearest to the point-in-time, wherein the journal entry is within a journal;

    synthesizing a recovery snapshot from the backup snapshot and the journal entry;

    providing the recovery snapshot in response to the request, wherein providing the recovery snapshot comprises exposing the recovery snapshot as a logical unit (“

    LU”

    );

    mounting the LU on a host device;

    receiving IOs for the LU from the host device;

    applying the IOs to the recovery snapshot to create a modified recovery snapshot;

    identifying a difference between the backup snapshot and the modified recovery snapshot, the difference comprising metadata journal entries associated with the IOsadding the metadata journal entries to a recovery list; and

    transmitting data associated with the metadata entries to a source storage system.

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