VOLUME CHANGE FLAGS FOR INCREMENTAL SNAPSHOTS OF STORED DATA
First Claim
1. A backup system for a Redundant Array of Independent Disks (RAID) storage system, the backup system comprising:
- a backup storage device that includes Copy-On-Write snapshots of a logical volume of the storage system; and
a backup controller operable to maintain flags for the logical volume that indicate whether extents at the logical volume have been modified since a previous snapshot was created, and to move the flags from the logical volume to a new Copy-On-Write snapshot of the volume when the new Copy-On-Write snapshot is created.
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Accused Products
Abstract
Methods and structure are provided for tracking changes to a logical volume over time. One exemplary embodiment is a backup system for a Redundant Array of Independent Disks (RAID) storage system. The backup system includes a backup storage device that includes Copy-On-Write snapshots of a logical volume of the storage system. The backup system also includes a backup controller. The backup controller is able to maintain flags for the logical volume that indicate whether extents at the logical volume have been modified since a previous snapshot was created, and to move the flags from the logical volume to a new Copy-On-Write snapshot of the volume when the new Copy-On-Write snapshot is created. This preserves information describing which extents of the logical volume changed between the creation of the new snapshot and the previous snapshot.
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Citations
20 Claims
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1. A backup system for a Redundant Array of Independent Disks (RAID) storage system, the backup system comprising:
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a backup storage device that includes Copy-On-Write snapshots of a logical volume of the storage system; and a backup controller operable to maintain flags for the logical volume that indicate whether extents at the logical volume have been modified since a previous snapshot was created, and to move the flags from the logical volume to a new Copy-On-Write snapshot of the volume when the new Copy-On-Write snapshot is created. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for backing up a Redundant Array of Independent Disks (RAID) logical volume, comprising:
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identifying an incoming Input/Output operation that will modify an extent of a logical volume; setting a flag for the extent at the logical volume if the extent has been modified at the logical volume since a previous Copy-On-Write snapshot of the volume was created; creating a new Copy-On-Write snapshot of the logical volume; and moving the flags from the volume to the new Copy-On-Write snapshot of the volume when the new Copy-On-Write snapshot is created. - View Dependent Claims (10, 11, 12, 13, 14, 15, 17, 18, 19, 20)
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16. A non-transitory computer readable medium embodying programmed instructions which, when executed by a processor, are operable for performing a method for backing up a Redundant Array of Independent Disks (RAID) volume, the method comprising:
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identifying an incoming Input/Output operation that will modify an extent of a logical volume; setting a flag for the extent at the logical volume if the extent has been modified at the logical volume since a previous Copy-On-Write snapshot of the volume was created; creating a new Copy-On-Write snapshot of the logical volume; and moving the flags from the volume to the new Copy-On-Write snapshot of the volume when the new Copy-On-Write snapshot is created.
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Specification