Creating a snapplan (dbed_vmchecksnap)
The dbed_vmchecksnap command creates a snapplan that dbed_vmsnap uses to create a snapshot of an Oracle database. The snapplan specifies snapshot scenarios (such as online, offline, or instant ).
You can name a snapplan file whatever you choose. Each entry in the snapplan file is a line in parameter=argument format.
When using dbed_vmchecksnap to create or validate a snapplan, the following parameters are set:
Parameter values for dbed_vmchecksnap
|
Parameter
|
Value
|
|---|
SNAPSHOT_VERSION
|
Specifies the snapshot version for this major release of Storage Foundation 5.0 for Oracle RAC.
|
PRIMARY_HOST
|
The name of the host where the primary database resides.
|
SECONDARY_HOST
|
The name of the host where the database will be imported.
|
PRIMARY_DG
|
The name of the VxVM disk group used by the primary database.
|
SNAPSHOT_DG
|
The name of the disk group containing the snapshot volumes.
The snapshot volumes will be put into this disk group on the primary host and deported. The secondary host will import this disk group to start a clone database.
|
ORACLE_SID
|
The name of the Oracle database. By default, the name of the Oracle database is included in the snapplan.
|
ARCHIVELOG_DEST
|
The full path of the archive logs.
There are several archive log destinations that can be used for database recovery if you are muliplexing the archive logs. You must specify which archive log destination to use.
It is recommended that you have the archive log destination on a separate volume if SNAPSHOT_ARCHIVE_LOG is yes.
|
SNAPSHOT_ARCHIVE_LOG
|
yes or no
Specifies whether to create a snapshot of the archive log volumes. Specify yes to split the archive log volume mirrors and deport them to the secondary host. When using the Oracle remote archive log destination feature to send the archive logs to the secondary host, you can specify no to save some space.
Because the archive logs may not always be delivered to the secondary host reliably, it is recommended that you specify yes.
|
SNAPSHOT_MODE
|
online or offline or instant
Specifies whether the database snapshot should be online, offline, or instant.
If the snapshot is created while the database is online, the dbed_vmsnap command will put the tablespaces into backup mode. After dbed_vmsnap finishes creating the snapshot, it will take the tablespaces out of backup mode, switch the log files to ensure that the extra redo logs are archived, and create a snapshot of the archived logs.
If the database if offline, it is not necessary to put the tablespaces into backup mode. The database must be shut down before creating an offline snapshot.
If the database snapshot is instant, dbed_vmsnap will skip putting the tablespace into backup mode.
Note
If SNAPSHOT_MODE is set to offline or instant, a two-host configuration is required and the -r relocate_path option is not allowed.
|
SNAPSHOT_PLAN_FOR
|
The default value is database and cannot be changed.
Specifies the database object for which you want to create a snapshot.
|
SNAPSHOT_PLEX_TAG
|
Specifies the snapshot plex tag. Use this variable to specify a tag for the plexes to be snapshot. The maximum length of the plex_tag is 15 characters. The default plex tag is dbed_flashsnap.
|
SNAPSHOT_VOL_PREFIX
|
Specifies the snapshot volume prefix. Use this variable to specify a prefix for the snapshot volumes split from the primary disk group. A volume name cannot be more than 32 characters. You should consider the length of the volume name when assigning the prefix.
|
ALLOW_REVERSE_RESYNC
|
yes or no
By default, reverse resynchronization is off (set equal to no). If it is set to yes, data from the snapshot volume can be used to update the primary volume.
|
SNAPSHOT_MIRROR
|
Specifies the number of plexes to be snapshot. The default value is 1.
|
When you first run dbed_vmchecksnap, use the -o setdefaults option to create a snapplan using default values for variables. You may then edit the file manually to set the variables for different snapshot scenarios.
Note
You cannot access Database FlashSnap commands (dbed_vmchecksnap, dbed_vmsnap, and dbed_vmclonedb) with the SFDB menu utility.
Before creating a snapplan, make sure the following conditions have been met:
Prerequisites
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|
Usage Notes
| -
The snapplan must be created on the primary host.
-
After creating the snapplan using the
dbed_vmchecksnap command, you can use a text editor to review and update the file, if necessary.
-
It is recommended that you create a local working directory to store your snapplans in.
-
See the
dbed_vmchecksnap (1M) online manual page for more information.
-
If the
SNAPSHOT_MODE for the database is set to online, the primary and secondary hosts can be the same. If the SNAPSHOT_MODE is set to offline or instant, the primary and secondary hosts must be different.
|
To create a snapplan
-
Change directories to the working directory you want to store your snapplan in.
$ cd /working_directory
-
Create a snapplan with default values using the
dbed_vmchecksnap command:
$ /opt/VRTS/bin/dbed_vmchecksnap -S ORACLE_SID \
-H ORACLE_HOME -f SNAPPLAN -o setdefaults -t host_name \
[-p PLEX_TAG]
-
Open the snapplan file in a text editor and modify it as needed.
In this example, a snapplan, snap1, is created for a snapshot image in a single-host configuration and default values are set. The host is named host1 and the working directory is /export/snap_dir.
$ cd /export/snap_dir
$ /opt/VRTS/bin/dbed_vmchecksnap -S PROD \
-H /oracle/product/9i -f snap1 -o setdefaults -t host1
Snapplan snap1 for PROD.
=====================================================
SNAPSHOT_VERSION=5.0
PRIMARY_HOST=host1
SECONDARY_HOST=host1
PRIMARY_DG=PRODdg
SNAPSHOT_DG=SNAP_PRODdg
ORACLE_SID=PROD
ARCHIVELOG_DEST=/prod_ar
SNAPSHOT_ARCHIVE_LOG=yes
SNAPSHOT_MODE=online
SNAPSHOT_PLAN_FOR=database
SNAPSHOT_PLEX_TAG=dbed_flashsnap
SNAPSHOT_VOL_PREFIX=SNAP_
ALLOW_REVERSE_RESYNC=no
SNAPSHOT_MIRROR=1
In this other example, a snapplan, snap2, is created for a snapshot image in a two-host configuration, and default values are set. The primary host is host1, the secondary host is host2, and the working directory is /export/snap_dir.
$ cd /export/snap_dir
$ /opt/VRTS/bin/dbed_vmchecksnap -S PROD \
-H /oracle/product/9i -f snap2 -o setdefaults -t host2
Snapplan snap2 for PROD.
=====================================================
SNAPSHOT_VERSION=5.0
PRIMARY_HOST=host1
SECONDARY_HOST=host2
PRIMARY_DG=PRODdg
SNAPSHOT_DG=SNAP_PRODdg
ORACLE_SID=PROD
ARCHIVELOG_DEST=/mytest/arch
SNAPSHOT_ARCHIVE_LOG=yes
SNAPSHOT_MODE=online
SNAPSHOT_PLAN_FOR=database
SNAPSHOT_PLEX_TAG=dbed_flashsnap
SNAPSHOT_VOL_PREFIX=SNAP_
ALLOW_REVERSE_RESYNC=no
SNAPSHOT_MIRROR=1
By default, a snapplan's SNAPSHOT_PLEX_TAG value is set as dbed_flashsnap. You can use the -p option to assign a different tag name. Make use of the -p option when creating the snapplan with the setdefaults option.
In the following example, the -p option is used with setdefaults to assign my_tag as the SNAPSHOT_PLEX_TAG value.
# dbed_vmchecksnap -S $ORACLE_SID -H $ORACLE_HOME -O setdefaults \
-p my_tag -f snap1 -t PROD
Snapplan snap1 for PROD
=====================================================
SNAPSHOT_VERSION=5.0
PRIMARY_HOST=host1
SECONDARY_HOST=host2
PRIMARY_DG=PRODdg
SNAPSHOT_DG=SNAP_PRODdg
ORACLE_SID=PROD
ARCHIVELOG_DEST=/arch_data
SNAPSHOT_ARCHIVE_LOG=yes
SNAPSHOT_MODE=online
SNAPSHOT_PLAN_FOR=database
SNAPSHOT_PLEX_TAG=my_tag
SNAPSHOT_VOL_PREFIX=SNAP_
ALLOW_REVERSE_RESYNC=no
SNAPSHOT_MIRROR=1
