Shrinking a Logical Volume

Caution: The procedure in this section can result in the loss of data if it is not performed properly. It is recommended only for experienced IRIX system administrators. Follow this procedure to remove one or more partitions from a logical volume:

1. Back up all files on the logical volume to tape or another filesystem. The entire logical volume is erased during this procedure.

2. Make a list that contains the controller, drive address, and partition number of each partition in the logical volume by looking at the /etc/lvtab entry for the volume.

3. For each controller and drive address pair in your list, follow the procedure in the section "Removing Files in the Volume Header With dvhtool" in Chapter 2 to remove one or more logical volume labels. These logical volume labels (files) are called lvlab<n>, where <n> is a partition number of a partition on this disk that is included in the logical volume you are removing.

4. Modify the /etc/lvtab entry for this logical volume so that it includes only the disk partitions that you want to include in the "shrunk" logical volume.

5. Give the mklv command to re-create the logical volume labels for the shrunk logical volume:

   # mklv volume_device_name

   volume_device_name is the first entry in the /etc/lvtab entry for this logical volume.

6. Make a filesystem on the logical volume by using the instructions in either the section "Making an XFS Filesystem" or the section "Making an EFS Filesystem" in Chapter 4.

7. Restore the files from the original logical volume to the shrunk logical volume. Be aware that the files from the original logical volume may no longer fit on the shrunken logical volume.