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SOS - Space-Optmized Snapshots using vxsfadm


vxsfadm -s sos -a <app_name> --<app_id> <value> --sos_name <config_name> -o <operation> [ --config_param <value> ... ]

vxsfadm -s sos -a <app_name> -c <config_file> -o <operation> [ --config_param <value> ... ]


Space-Optimized Snapshot (SOS) service lets you create a point-in-time copy of an application instance, for example, a database instance. Unlike traditional full-sized snapshot service SOS requires a fraction of the total storage to create a replica of an application instance. On the other hand, being an incremental backup, SO snapshot cannot be moved to off host. Although SOS service can be used for any application in theory, this document is targeted at Oracle database users willing to use SOS service.

Space-optimized database snapshot service uses VxVM (Veritas Volume Manager) space-optimized instant snapshots. User needs to prepare volumes participating in the snapshot for instant snapshots. Also, at least one cache object per diskgroup is required to exercise space-optimized snapshots.


SETDEFAULTS Generates the default configuration file for application.
VALID Validate is the basic validation stage which evaluates the setup of the corresponding application (Oracle) and the system on which the snapshot operations are to be performed.

Operation alias : VALIDATE

SNAP Takes a space-optmized snapshot of volumes using cache object.

Operation alias : SNAPSHOT

MOUNT Mounts the volume at specified location (See configuration parameter CLONE_PATH). If the mount location is not specified, it will mount the snapshot in /tmp.

Operation alias : SNAPMOUNT

UNMOUNT Unmount mounted snapshots.


PRECLONE Oracle specific operation, where database is opened in mount state without applying archive log.

Operation alias : MOUNTDB

CLONE Clone the application to a new instance. New instance can be named using parameter CLONE_NAME. If no name is specified, a default name for the clone will be generated.

Operation alias : CLONEDB

DESTROY Destroy the snapshot.

Operation alias : DELETE, REMOVE

LIST Lists available snapshot configurations.


Configuration parameters allow users to control snapshot operation. Almost all of the configuration parameters are optional (with the exception of application instance name and configuration name). Parameters can be specified in a configuration file (using ’-c <configfile>’ option of vxsfadm) or as command-line arguments (command line option) to vxsfadm. Following is the list of parameters for Oracle database snapshot service.


Description User-defined name of the snapshot configuration. This name is used for referring a particular snapshot for performing any operation. It is also used in listing snapshots (vxsfadm -o list option).
Valid Values Character string. Ex. snap1. This parameter is not optional.
Command line option --sos_name <value> or --name <value>


Description Version of snapplan or snapshot configuration.
Valid Values <number>.<number> Ex. 6.0
Command line option none


Description Session ID of Oracle database for which snapshot is to be taken.
Valid Values Character string. Ex. orcldb. This parameter is not optional. It can be specified as environment variable.
Command line option --oracle_sid <value> or -S <value>


Description Oracle home parameter of the corresponding Oracle SID.
Valid Values Valid path. Ex. /oracle/11gr2. This parameter is not optional. It can be specified as environment variable.
Command line option --oracle_home <value> or -H <value>


Description Mode of application when snapshot operation is to be performed.
Valid Values Offline, online or instant Default value is online.
Command line option --app_mode <value> or --online | offline | instant


Description Name of application instance that is be created during clone operation.
Valid Values Character string. Ex. clone1 If not specified, clone name is auto-generated.
Command line option --clone_name=<value>


Description Filesystem path on which the clone application instance is to be mounted.
Valid Values Valid path. Ex. /tmp/cln If not specified, clone name is auto-generated.
Command line option --clone_path <value> or --mount_path <value> or --on <value> or --at <value>


Description Prefix for snapshot volumes.
Valid Values Character string. Ex. SNP_ Default prefix is SNAP_.
Command line option --snapshot_vol_prefix <value> or --prefix <value>


Description Specifies comma separated values of diskgroup and corresponding cache object.
Valid Values <dgname>:<cachename>,a\k:^XX. Ex: testdg1:C1,testdg2:C2 By default, cache objects will be auto-detected.
Command line option --cache_object <value> or --co <value>


Description Specifies whether Oracle archive log volumes are to be included in snapshot.
Valid Values Yes or no Default is yes.
Command line option --snapshot_archive_log y|n or --snapshot_archive_log or --no_snapshot_archive_log


Description This paramater can be used to specify the pfile used by the primary database. If not specified the default pfile is assumed
Command line option --pfile=<filepath>


Description This paramater specifies the file containing the modified pfile attributes to e used in the clone database.
Command line option --pfile_mod=<filepath>


1. Create a default configuration file

$ vxsfadm -s sos -a oracle -o setdefaults --oracle_sid mydb --oracle_home /home/oracle/11gr2/app --sos_name daily_snap -c dailyconfig

This will create a default configuration file with all the parameters and default values. If required, user can modify the parameters otherwise the file can be used as is.

Note: If ORACLE_SID and ORACLE_HOME parameters are exported in environment, there is no need to mention it on command line. In the following examples, we assume that ORACLE_SID and ORACLE_HOME parameters are available from the environment.

2. Validate database and system setup for SOS using default options:

$ vxsfadm -s sos -a oracle -o validate --sos_name daily_snap

Use a configuration file for customizing snapshot configuration:

$ vxsfadm -s sos -a oracle -o validate -c dailyconfig

Validation for instant mode snapshot

$ vxsfadm -s sos -a oracle -o validate --name daily_snap --instant

3. Create a snaphot

$ vxsfadm -s sos -a oracle -o snap --sos_name daily_snap

This step would create space-optmized snapshot volumes from the primary volumes using specified cache objects.

Note: All the parameters are read and stored at validation stage in repository, including mandatory parameters --oracle_sid and --sos_name. In case user needs to change anything please change the configuration file and use -c option along with the above command.

$ vxsfadm -s sos -a oracle -o snap -c dailyconfig

4. Mount snapshot

$ vxsfadm -s sos -a oracle -o mount --sos_name daily_snap

This command would mount the snapshot on the host running database instance. By default, snapshot volumes would be mounted in /tmp filesystem.

If user needs to specify alternate mount location, either provide CLONE_PATH on command line or from the config file as:

$ vxsfadm -s sos -a oracle -o mount --sos_name daily_snap --clone_path /cloneoracle

Make sure /cloneoracle directory exists and has appropriate permissions for oracle user.

If the configuration file exists, user can use

$vxsfadm -s sos -a oracle -o mount -c dailyconfig

5. Clone database on snapshot

$ vxsfadm -s sos -a oracle -o clone --sos_name daily_snap --clone_name newclone

If user has already specified the clone_name and clone_path in configuration file which was used during VALIDATE state, --clone_name is not required on command line.

$ vxsfadm -s sos -a oracle -o clone --sos_name daily_snap --clone_name newclone

If the configuration file is present:

$ vxsfadm -s sos -a oracle -o clone -c dailyconfig


Using space-optimized snapshots for replicated databases using Volume Replicator (VVR)

Generate a snapshot configuration to be used on secondary site for cloning replicated database.

[On Primary Site] $ /opt/VRTSdbed/bin/vxsfadm -a oracle -o getvvrinfo

Use this configuration to clone replicated database locally on VVR secondary site.

[On Secondary Site]

For instant mode snapshots: $ /opt/VRTS/bin/vxsfadm -s sos -a oracle -c config.xyz -o clone

Once the snapshot configuration is validated on VVR secondary site, subsequent operations can proceed as in ordinary SOS.

For online mode snapshots, create an online mode snapshot to be used as golden image: $ /opt/VRTS/bin/vxsfadm -s flashsnap -a oracle -c config.xyz -o snapshot --name flash1 --extra datadg:cacheobj

Then create space-optimized clone database instances using above snapshot as source: $ /opt/VRTS/bin/vxsfadm -s sos -a oracle --source-snapshot flash1 -c config.xyz -o clone --name sos1


vxsfadm (1M), vxsfadm-oracle(1M), vxsfadm-sos (1M)

vxsfadm-flashsnap (1M), vxsfadm-checkpoint (1M), vxsfadm-filesnap (1M) vxsfadm-oracle-flashsnap (1M), vxsfadm-oracle-checkpoint (1M), vxsfadm-oracle-filesnap (1M)

Storage Foundation vxsfadm-oracle-sos(1M)