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How to determine which Snapshot copies to delete on the basis of size

You can use the snap list command output to determine which Snapshot copies to delete to free the most disk space.

Before trying to conserve space by deleting a large Snapshot file, you should examine the cumulative values in the snap list output. If two adjacent Snapshot files show little difference in their cumulative values, most of the data referenced by these Snapshot copies is the same. In this case, deleting only one of the Snapshot copies does not free much disk space.

In many cases, you can use the default Snapshot schedule and the default Snapshot reserve because these settings are appropriate for most environments. When you create a new volume, the new volume inherits the Snapshot schedule from the root volume. After you use the volume for several days, check how much disk space the Snapshot copies are consuming in the volume. If the amount seems high, you can decrease the amount of time that Snapshot copies are kept or increase the Snapshot reserve.

As you use Snapshot copies, you should continue to watch the statistics change over time. The statistics help you gain a better understanding of how Snapshot copies use disk space.

Attention: As a general rule, you should avoid deleting Snapshot copies that are not the product of the snap sched command (for example, Snapshot copies generated by SnapMirror or SnapVault commands). Deleting these Snapshot copies could halt the SnapMirror or SnapVault processes. An exception would be Snapshot copies left over from old SnapMirror relationships that you no longer want to maintain.