Commands Reference, Volume 1

backsnap Command

Purpose

Provides an interface to create a snapshot for a JFS2 file system and perform a backup of the snapshot.

Syntax

backsnap [ -R ] -m MountPoint -s size=Size [ BackupOptions ] FileSystem

Description

Provides an interface to create a snapshot for a JFS2 file system and perform a backup of the snapshot.

Flags

-m MountPoint	Specifies the path of where the snapshot created should be mounted.
-R	Specifies that the snapshot created by this command will be removed when the backup completes.
-s size=Size	Specifies the size to create the new logical volume. If Size is followed by an M the value is treated as megabytes. If Size is followed by a G the value is treated as gigabytes. Otherwise the value is treated as 512-byte blocks.

Parameters

BackupOptions

Any other options are passed to the backup command when the backup of the snapshot is performed. Minimally it is required to specify the type of backup desired.

For backup by name the -i option must be specified along with the device for the backup.

For backup by inode the level option, -[0-9], must be specified along with the device for the backup.

FileSystem

Specifies the JFS2 file system to create a snapshot of and backup.

Exit Status

0: The command completed successfully.
>0: An error occurred.

Examples

To create a snapshot for the /home/janet/sb file system and backup it up by name, enter:
```
 backsnap -m /tmp/snapshot/janetsb -s size=16M -i -f/dev/rmt0 /home/janet/sb 
```
This command creates a logical volume of size 16 megabytes and then creates a snapshot for the /home/janet/sb file system on the newly created logical volume. It then mounts the snapshot on /tmp/snapshot/janetsb and backups the files and directories in that file system by name to the /dev/rmt0 device.
To create a snapshot for the /home/janet/sb file system and backup it up by inode, enter:
```
 backsnap -R -m /tmp/snapshot/janetsb -s size=16M -0 -f /dev/rmt0 /home/janet/sb 
```
This command creates a logical volume of size 16 megabytes and then creates a snapshot for the /home/janet/sb file system on the newly created logical volume. It then mounts the snapshot on /tmp/snapshot/janetsb and backups the data in the snapshot by inode to the /dev/rmt0 device. After the backup completes the snapshot is deleted.

Files

/usr/sbin/backsnap

Contains the backsnap command.

Related Information

The backup command, snapshot command.