< Previous  | TOC | Index | Next  >

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 -t 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 -t vxfs -o ckpt=may_23,remount,rw \
/dev/vx/dsk/fsvol/vol1:may_23 /fsvol_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 this Storage Checkpoint automatically when the system starts up, put the following entries in the /etc/fstab file:

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, you must also use the -o cluster option:

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

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(1M) manual page.

Storage Checkpoints can be unmounted by the mount point or pseudo device name:

# 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.