3-24 Dell PowerVault 720N, 740N, and 760N System Administrator and Command Reference Guide
For example, vol1 is the source volume for data replication and it contains two
snapshots: hourly.0 and filerA_vol1.2. If hourly.0 was taken earlier than
filerA_vol1.2 and you revert vol1 to hourly.0, you cannot find filerA_vol1.2 after the
reversion. As a result, the filer cannot start an incremental update of the mirror. It
must re-create the baseline version of the mirror.
(IIHFWVRI5HYHUWLQJD5RRW9ROXPH
Because the /etc directory of the root volume contains configuration information
about the filer, reverting the root volume might change the filer configuration. The fol-
lowing list describes the effects of reverting the root volume:
The volume loses the changes that were made to the /etc directory after the
snapshot creation time. Suppose you change the IP address of an interface on
the filer after the hourly.0 snapshot was taken. If you revert the root volume to
the hourly.0 snapshot, the filer reboots with the old IP address for the interface.
The options used for the entire filer are reverted to the settings that were in
effect when the snapshot was taken.
Recommendations: Avoid reverting the configuration files. To avoid reverting the
configuration files, follow one of these steps:
Store all data that might need to be reverted in a volume other than the root vol-
ume. This ensures that you never need to revert the root volume.
If the data you want to revert resides in the root volume, back up the /etc direc-
tory to another volume or another filer before using SnapRestore. After you revert
the volume, restore the /etc directory and reboot the filer.
If you back up the /etc directory to another volume, you can use the
vol options
volume
root command to make the filer reboot with that vol-
ume as the root volume. In this way, when the filer reboots during the reversion,
it can use the correct settings in the /etc directory.
(IIHFWVRI6QDS5HVWRUHRQ)LOHU%DFNXSDQG5HFRYHU\
Because all files in a reverted volume have timestamps that are the same as those
when the snapshot was created, the filers dump and restore commands might be
affected. Incremental backup and restore operations can no longer rely on the times-
tamps to determine what data needs to be backed up or restored.
Recommendation: After you revert a volume, perform a level-0 backup of the vol-
ume. After the level-0 backup is finished, the filer can perform subsequent
incremental backups correctly. Also, if you need to restore data from tape to this vol-
ume, use only the backups created after the volume reversion.