Dell PowerVault MD3860f - Manual (Page 17)

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Snapshot Repository Sizing
A new feature of firmware 07.83 are Point-in-Time Snapshots. These provide the ability to roll-back snapshots to
previous point-in-time saves and optimize the data changes between snapshot images. This feature utilizes two
separate repositories to facilitate tracking of changes to the base volume. They are the Snapshot Group repository and
Snapshot Volume repository.
Snapshot Group Repository
The Snapshot Group repository is used to track data changes to the base volume (volume that the Snapshot Image was
created from). The Snapshot Group repository may contain multiple Snapshot Images (point-in-time records of base
volume). A Snapshot Volume is created from these images and can then be mapped to a host for access.
Figure 10. Modular Disk Storage Manager (MDSM) Snapshot Group View
Snapshot Volume Repository
The Snapshot Volume repository is used to track data changes to the Snapshot Volume, if read/write access is allowed.
Once a Snapshot Volume is mapped to a host for access any changes to the volume are tracked within this repository.
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