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Storage Foundation Cluster File System High Availability 7.2 Administrator's Guide - Solaris

Last Published: 2018-03-06

Product(s): InfoScale & Storage Foundation (7.2)

Platform: Solaris

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 must write to a Storage Checkpoint, mount it using the -o rw option.
If a Storage Checkpoint is currently 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.

If older Storage Checkpoints already exist, write activity to a writable Storage Checkpoint can generate copy operations and increased space usage in the older Storage Checkpoints.

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

To mount a Storage Checkpoint of a cluster file system, you must also use the -o cluster option:
```
  # mount -F 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_vxfs(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.