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Accessing a Storage Checkpoint

You can mount Storage Checkpoints using the mount command with the mount option -o ckpt=ckpt_name.

See the mount_vxfs(1M) manual page.

Observe the following rules when mounting Storage Checkpoints:

• Storage Checkpoints are mounted as read-only Storage Checkpoints by default. If you need to write to a Storage Checkpoint, mount it using the -o rw option.
• If a Storage Checkpoint is originally mounted as a read-only Storage Checkpoint, you can remount it as a writable Storage Checkpoint using the -o remount option.
• To mount a Storage Checkpoint of a file system, first mount the file system itself.
• To unmount a file system, first unmount all of its Storage Checkpoints.
  Warning: If you create a Storage Checkpoint for backup purposes, do not mount it as a writable Storage Checkpoint. You will lose the point-in-time image if you accidently write to the Storage Checkpoint.
  

A Storage Checkpoint is mounted on a special pseudo device. This pseudo device does not exist in the system name space; the device is internally created by the system and used while the Storage Checkpoint is mounted. The pseudo device is removed after you unmount the Storage Checkpoint. A pseudo device name is formed by appending the Storage Checkpoint name to the file system device name using the colon character (:) as the separator.

For example, if a Storage Checkpoint named may_23 belongs to the file system residing on the special device /dev/vx/dsk/fsvol/vol1, the Storage Checkpoint pseudo device name is:

/dev/vx/dsk/fsvol/vol1:may_23

• To mount the Storage Checkpoint named may_23 as a read-only (default) Storage Checkpoint on directory /fsvol_may_23, type:

# mount -F vxfs -o ckpt=may_23 /dev/vx/dsk/fsvol/vol1:may_23 \
/fsvol_may_23

  Note   The vol1 file system must already be mounted before the Storage Checkpoint can be mounted.

• To remount the Storage Checkpoint named may_23 as a writable Storage Checkpoint, type:

# mount -F vxfs -o ckpt=may_23,remount,rw \
/dev/vx/dsk/fsvol/vol1:may_23 /fsvol_may_23

• To mount this Storage Checkpoint automatically when the system starts up, put the following entries in the /etc/vfstab file:

   

  #device to mount	device to fsck	mount point	FS type	fsck pass	mount at boot	mount options
  /dev/vx/dsk/    fsvol/vol1	/dev/vx/rdsk/    fsvol/vol1	/fsvol	vxfs	1	yes	—
  /dev/vx/dsk/fsvol/    vol1:may_23	—	/fsvol_may_23	vxfs	0	yes	ckpt=  may_23

Device-Special-File	Mount-point	fstype	options	backup- frequency	pass-number
/dev/vx/dsk/fsvol/vol1	/fsvol	vxfs	defaults	0	0
/dev/vx/dsk/fsvol/vol1:may_23	/fsvol_may_23	vxfs	ckpt=may23	0	0

• To mount a Storage Checkpoint of a cluster file system, use the -o cluster option:

# mount -F vxfs -o cluster,ckpt=may_23 \
/dev/vx/dsk/fsvol/vol1:may_23 /fsvol_may_23

  Note   You can only mount a Storage Checkpoint cluster-wide if the file system that the Storage Checkpoint belongs to is also mounted cluster-wide. Similarly, you can only mount a Storage Checkpoint locally if the file system that the Storage Checkpoint belongs to is mounted locally.

You can unmount Storage Checkpoints using the umount command.

See the umount_vxfs(1M) manual page.

• Unmount storage checkpoints by the mount point or pseudo device name, as follows.

# umount /fsvol_may_23

# umount /dev/vx/dsk/fsvol/vol1:may_23

  Note   You do not need to run the fsck utility on Storage Checkpoint pseudo devices because pseudo devices are part of the actual file system.