Use vob_snapshot_setup to control VOB database snapshot activity on each VOB host. By default, the scheduler runs vob_snapshot periodically. When vob_snapshot runs on a VOB host, it checks each locally stored VOB for the existence of a multipart string attribute that specifies snapshot parameters. A VOB's database is copied by vob_snapshot only if this attribute has been applied to the VOB with vob_snapshot_setup. Use vob_snapshot_setup lsvob to list the local VOBs currently processed by vob_snapshot and, with –long, to display the snapshot parameters for each VOB in the list.
Use vob_snapshot_setup modparam to add a VOB to the database snapshot list, or to change snapshot parameters for a VOB already on the list. (You cannot modify individual parameters with modparam, but must replace them all.)
Use vob_snapshot_setup rmparam to remove a VOB from the snapshot list.
See also vob_snapshot and vob_restore.
Warning: Do not run vob_snapshot_setup on a V2.x VOB, until you have reformatted the VOB for V3 with reformatvob, and you are certain that checkvob –setup has completed successfully. checkvob –setup updates storage container names and verifies the presence of V3 type managers. If either operation fails, checkvob cannot synchronize a database snapshot at vob_restore time. If you are using a homegrown or third-party type manager, code that implements the get_cont_info method must be added to the type manager so that elements managed by the type manager can be processed by checkvob at vob_restore time.
An administrator uses vob_snapshot_setup modparam to apply the following snapshot parameters to each VOB or replica for which database snapshots are to be taken:
Parameter | Valid Values | Default Value |
---|---|---|
–snap_to | Existing, writable directory pathname | No default |
–dbcheck | yes | no | No |
–notify (UNIX only) | Comma-separated list | Empty list |
These parameters are combined to form a single string attribute of type vob_snapshot_parameters, which vob_snapshot_setup attaches to the VOB.
Here is how these parameters may appear in a vob_snapshot_setup lsvob –long listing:
VobTag: /vobs/src
...
Dbcheck Enabled: yes
Notification List: root user,clearadm,anne
Snap To: /net/saturn/usr1/snapshots
...
For more information, see the –snap_to, –dbcheck, and –notify options.
The VOB snapshot backup/restore scenario requires additional disk space, both at restore time and during daily operation:
The replica UUID subdirectory that stores a VOB's database snapshot is overwritten the next time vob_snapshot processes that VOB.
Typically, the –snap_to directory gets backed up as part of normal backup operations some time after the snapshots are taken.
vob_snapshot runs db_check to perform fundamental database consistency and integrity checks. (Later, at restore time, checkvob may examine the VOB database looking for ClearCase and ClearCase LT anomalies.) The db_check pass occurs after all snapshots are completed on the local host. Because this check can be time-consuming, it is disabled by default.
If vob_snapshot cannot lock the database and db_check is disabled, db_check runs on the snapshot at vob_restore time. Running db_check earlier, at snapshot time, may expose problems that you would prefer not to encounter at recover time.
Note: In the UNIX examples that follow, arguments and output that show multicomponent VOB tags are not applicable to ClearCase LT, which recognizes only single-component VOB tags. In this manual, a multicomponent VOB tag is by convention a two-component VOB tag of the form /vobs/vob-tag-leaf—for example, /vobs/src. A single-component VOB tag consists of a leaf only—for example, /src. In all other respects, the examples are valid for ClearCase LT.
cd c:\Program Files\Rational\ClearCase\etc
vob_snapshot_setup lsvob –long
VobTag: \vob_src
Replica Name: original
Replica Uuid: 4a6bbe5d88d511cfa9b400018073db6f
Family Uuid: 4a6bbe5988d511cfa9b400018073db6f
Dbcheck Enabled: yes
Snap To: \\saturn\bigdisk\snapshot
Deferred Deletes: Enabled
VobTag: \vob_lib
Replica Name: original
Replica Uuid: 5fec90f48db911cfab9800018073db6f
Family Uuid: 5fec90f08db911cfab9800018073db6f
Dbcheck Enabled: no
Snap To: \\saturn\bigdisk\snapshot
Deferred Deletes: Enabled
vob_snapshot_setup modparam /vob/src
Supply a directory to contain the snapshot data for this vob.
The directory must exist and be writable.
(Full pathname: there is no default) /net/saturn/usr1/snaps/src
Supply a comma separated list of those users to be notified of
events during the snapshot of this vob.
(Comma separated user id list: default no one): root,clearadm,anne
Do you want a data base check to be performed on this vob after
all snapshot operations on this host are completed?
Valid responses are (yes,no)
The default is no: yes
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