3-22 Dell PowerVault 720N, 740N, and 760N System Administrator and Command Reference Guide
Using either of these methods takes a longer time than reverting the volume. This is
because with SnapRestore, no data needs to be copied; the file system is just put
back in its earlier state.
SnapRestore is a licensed feature. You must purchase and install the license code
before you can use it.
+RZ6QDS5HVWRUH:RUNV
After you select a snapshot for reversion, the filer reboots with the volume containing
the same data and timestamps as it did when the snapshot was taken. All data that
exists before you initiate the reversion is overwritten.
&$87,21<RXFDQQRWXQGRWKHUHYHUVLRQWRFKDQJHWKHYROXPHEDFNWRWKH
VWDWHLWZDVLQEHIRUHWKHUHYHUVLRQ
:KDW6QDS5HVWRUH5HYHUWV
SnapRestore reverts only the file contents. It does not revert attributes of a volume.
For example, the snapshot schedule, volume option settings, RAID group size, and
maximum number of files remain unchanged after the reversion.
Option settings applicable to the entire filer, however, might be reverted. This is
because the option settings are stored in a registry in the /etc directory. If you revert
the root directory, the registry is reverted to the version that was in use at the snap-
shot creation time. For more information about how reverting a root volume works,
refer to Effects of Reverting a Root Volume.
)LOHV7KDW6QDS5HVWRUH&DQQRW5HFRYHU
You cannot revert a volume to recover a deleted snapshot. For example, if you delete
the hourly.2 snapshot and revert the volume to the hourly.1 snapshot, you cannot find
the hourly.2 snapshot after the reversion. Although the hourly.2 snapshot existed at
the creation time of the hourly.1 snapshot, SnapRestore cannot revert the contents of
the hourly.2 snapshot because you already deleted it.
+RZ6QDS5HVWRUH$IIHFWV5HFHQW6QDS6KRWV
After you revert a volume to a particular snapshot, you lose the snapshots that are
more recent than the snapshot used for the volume reversion. For example, after you
revert the volume to the hourly.1 snapshot, you no longer have access to more recent
snapshots, such as the hourly.0 snapshot. This is because at the creation time of the
hourly.1 snapshot, the hourly.0 snapshot did not exist.
7\SLFDO$SSOLFDWLRQVRI6QDS5HVWRUH
If a client application corrupts data files in a volume, you can revert the volume to a
snapshot taken before the data corruption. The following examples illustrate some sit-
uations in which you can apply SnapRestore to recover from corrupted data.