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Flashsnap - Third mirror break-off snapshots using vxsfadm


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

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


FlashSnap service helps to create a point-in-time copy of an application for backup and off-host processing. FlashSnap service lets you make backup copies of your application volumes online and with minimal interruption to users.

FlashSnap lets you capture an online image of an actively changing application at a given instant that is known as a snapshot. A snapshot copy of an application is referred to as an application snapshot. You can use an application snapshot on the same host or on a secondary host sharing the same storage. An application snapshot can be used for off-host processing tasks, such as backup, data warehousing, and decision-support queries. When the snapshot is no longer needed, the system administrator can import the original snapshot back to the primary host and resynchronize the snapshot to the original application volumes. Database FlashSnap commands are executed from the command line interface.

Flashsnap service provides traditional volume level Snapshot (Third mirror break-off, full sized snapshot)

Traditional snapshot creates a full size, volume-level snapshot image of an volume, by splitting the mirror volumes. One can use the snapshot image on either the same host where the application is running or on a secondary host, provided storage is shared by the two hosts.

Flashsnap service is supported on local mount and CFS mounts. User needs to tag a mirror which needs to be split. At the time of splitting the mirror, all the i/o to the volume would be frozen to get a consistent image of the volume. Splitting of mirror is a automic operation and is done in a fraction of a second.


SETDEFAULTS Generates the default configuration file for application. By default the output is printed to STDOUT. If the -c option is specified, then the configuration information is populated to the file specified by the -c option. If a file of the same name already exists , then an error regarding the same would be reported. In such a case speficy a different filename or remove the existing file. This operation does not add the configuration to the repository, hence the configuration would not be listed using vxsfadm -o list until the configuration is validated or used for any other operations.
VALID Validates the configuration file and environment.

Operation alias : VALIDATE

SNAP Breaks the mirror and splits the disk group.

Operation alias : SNAPSHOT, BREAK

MOUNT Mounts the Mirror volumes on specified mount point (See configuration parameter CLONE_PATH). If the mount location is not specified, it will mount the snapshot in /tmp.

Operation alias : SNAPMOUNT

UNMOUNT Umounts the snapshots, if clone is created, would shutdown the clone.

Operation alias : UMOUNT, SNAPUNMOUNT

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.
RESYNC Resyncs the mirror with primary volumes.
REVERSERESYNCBEGIN Mount snapshot volumes and bring up Oracle instance (preview session) using this operation. It allows user to verify backup data before restoring it onto primary volumes.

NOTE: Before performing reverse resynchronization, back up repository using sfua_rept_util tool. Also, if you make any structural change to database (e.g. adding a new datafile), then it is a good idea to back it up using FlashSnap snapshot commands.

Operation alias : RRBEGIN

REVERSERESYNCABORT End reverse resync preview session and get back to original data volumes.

Operation alias : RRABORT

REVERSERESYNCCOMMIT Commit reverse resync changes previewed in RRBegin operation. After this operation finishes, user cannot go back to original data volumes. It will permanently restore the snapshot volumes onto data volumes.

Operation alias : RRCOMMIT

LIST Lists available snapshot configurations.
DESTROY Destroys the flashsnap configuration from the repository, and the same would not longer appear in the listing (using vxsfadm -o list). This does not remove the configuration file, if any, that was created using setdefaults or manually.


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 flashsnap 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 --flashsnap_name <value> or --name <value>


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


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 Prefix for snapshot diskgroup(s).
Valid Values Character string. Ex. SNP_ Default prefix is SNAP_.
Command line option --snapshot_dg_prefix <value> or --prefix <value>


Description User needs to tag the mirror which is to be split during snapshot operation. If no mirror is tagged, snapshot operation would error out.
Valid Values Character string. Ex. snapshot_plex Default value is dbed_flashsnap.
Command line option --snapshot_plex_tag <value> or --plex <value>


Description Number of set of mirrors that have snapshot plex tag set.
Valid Values Number. Ex. 2 Default value is 1.
Command line option --snapshot_mirror <value> or --n <value>


Description Volume-to-mountpoint mapping provided by the user.
Valid Values <dg>:<vol>=<path>;<dg2> <vol2>=<path2>


Command line option --mapped_mounts=<dg>:<vol>=<path>; <dg>:<vol>=<path> or --map <dg>:<vol>=path or --map <dg>:vol=path


Description List of additional objects that must be included with the snapshot diskgroup. This is useful when using a flashsnap snapshot as a source for space-optimized snapshots. This is a comma separated list of objects. Each object is specified by joining the diskgroup and object names with a colon.
Valid Values <dg1>:<vol1>,<dg2>:<vol2>,...
Example datadg:cacheobj
Command line option --extra-objects=<dg>:<vol>,<dg2>:<vol2>


--extra <dg>:<vol> --extra <dg2>:<vol2>


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

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

Storage Foundation vxsfadm-flashsnap(1M)