vob_snapshot_setup

Sets or displays VOB database snapshot parameters

APPLICABILITY

ClearCase (administrative command), Attache (administrative command)

SYNOPSIS

• List local VOBs that are currently processed by vob_snapshot:

  ccase-home-dir\etc\vob_snapshot_setup lsvob [ -short | -long ] [ vob-tag ... ]

• Configure a VOB for vob_snapshot processing:

  ccase-home-dir\etc\vob_snapshot_setup modparam -snap_to snap-dir-pname

  
  

  { -dbcheck yes |-dbcheck no }  vob-tag

• Remove a VOB from the database snapshot list:

  ccase-home-dir\etc\vob_snapshot_setup rmparam vob-tag

DESCRIPTION

Use vob_snapshot_setup to control VOB database snapshot activity on each ClearCase VOB host. By default, the ClearCase 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: 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, or elements managed by the type manager cannot be processed by checkvob at vob_restore time.

Setting VOB Snapshot Parameters

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:

These parameters are combined to form a single ClearCase 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: \vob_src
...
Dbcheck Enabled:         yes
Snap To:                 \\saturn\bigdisk\snapshot
...

See the -snap_to and -dbcheck options for further details.

Disk Space Usage

The VOB snapshot backup/restore scenario requires additional disk space, both at restore time and during daily operation:

• At restore time, checkvob may require substantial disk space. See the checkvob reference page.
• Enabling VOB snapshots for a VOB also enables a deferred source container deletion mechanism, which typically increases source pool size. See vob_server for a description of deferred deletion.

PERMISSIONS AND LOCKS

Permissions Checking: No special permissions required.

Locks: A modparam or rmparam operation fails if any of the following objects are locked: VOB, vob_snapshot_parameters attribute type.

Mastership: If the VOB is replicated, it must be self-mastering.

OPTIONS AND ARGUMENTS

VOB LISTING REPORT FORMAT.   Default: vob_snapshot_setup lsvob lists the VOB-tag of each local VOB currently configured for database snapshot.

-short

Same as default.

-long

In addition to the VOB-tag, vob_snapshot_setup lsvob lists each VOB's snapshot parameters and additional VOB identity details. If multiple VOBs use the same parent -snap_to directory, use the replica UUID returned by -long to find a particular snapshot in the parent directory.

vob-tag ...

Space-separated list of VOBs; restricts listing to one or more local VOBs.

SPECIFYING THE VOB.   Default: None. modparam and rmparam operations require a VOB-tag argument.

vob-tag

The VOB's VOB-tag, as specified in mkvob or mktag -vob.

SETTING SNAPSHOT PARAMETERS.   Default: With modparam, you must specify a VOB-tag; if you specify no other options or arguments, modparam prompts for all necessary input and displays explanatory text. If you specify both a VOB-tag and a snapshot target directory, modparam does not prompt for additional parameters: vob_snapshot does not run the db_check operation.

-snap_to snap-dir-pname

A disk location to store the snapshot. vob_snapshot appends the VOB's replica UUID to the -snap_to directory to create a subdirectory, then copies the VOB database to the subdirectory (after checking for sufficient disk space).

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.

-dbcheck yes

-dbcheck no

Specifies whether to run the db_check utility on each snapshot.

vob_snapshot runs db_check to perform fundamental, non-ClearCase-related database consistency and integrity checks. (Later, at restore time, checkvob may examine the VOB database looking for ClearCase 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 you would prefer not to encounter at recover time.

EXAMPLES

• List all VOBs on the local host that are currently configured for processing by vob_snapshot.

cd c:\Program Files\Rational\ClearCase\etc

vob_snapshot_setup lsvob
\vob_src
\vob_lib

• Same as previous example, but expand the output to include each VOB's replica UUID and snapshot parameters.

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

• Add VOB \vob_src to the local host's snapshot list.

cd c:\Program Files\Rational\ClearCase\etc

vob_snapshot_setup modparam  -dbcheck yes
-snap_to \\saturn\bigdisk\snaps\vob_src   \vob_src

• Add \vob_src to the local host's snapshot list, as in the previous example, but this time run vob_snapshot_setup modparam in interactive mode.

vob_snapshot_setup modparam /vob/src\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) \\saturn\bigdisk\snaps\vob_src

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

• Remove VOB \vob_src from the local host's snapshot list.

cd c:\Program Files\Rational\ClearCase\etc

vob_snapshot_setup rmparam \vob_src

FILES

ccase-home-dir\var\log\snap_log

WINDOWS NT REGISTRY KEYS

HKEY_LOCAL_MACHINE\SOFTWARE\Atria\ClearCase\CurrentVersion\snapshot

SEE ALSO

checkvob, schedule, vob_restore, vob_snapshot