HP-UX System Administrator's Guide: Routine Management Tasks

Removing a Mirror from a Logical Volume
For detailed discussion of mirroring see HP-UX System Administrator’s Guide: Logical
Volume Management. The following is a quick reference; we’ll be using HP SMH.
1. Access the HP SMH Homepage.
2. Select Tools, Disks and File Systems, Logical Volumes. This will display a list
of the logical volumes.
3. Select the logical volume for which you want to remove one or more mirror data
images and click on the Remove Mirror(s)... action on the right side of the page.
This will display the Remove Mirror(s) page.
4. Enter the new desired number of mirror images. If there is only one mirror image,
enter “ 0”. If there are more than one mirror images and you are not deleting all
of them you can either select the ones to remove or have HP SMH select the images
to remove. Click Remove.
5. If the removal process is not successful, an error message will be displayed. If the
procedure was successful click on Done to return to the Logical Volumes page.
Check to see that the count in the Mirrors column has been updated for the logical
volume.
Replacing a Mirrored Disk in a Logical Volume
The following method uses pvchange to temporarily disable links to a disk. For an
alternate approach to replacing a mirror see HP-UX System Administrator’s Guide: Logical
Volume Management.
1. Before replacing the disk, minimize any potential loss of data due to its removal;
confirm that any mirrored logical volumes using the disk are mirrored onto a
separate disk and that those mirror copies are current. You can find the list of
logical volumes using the disk using pvdisplay:
pvdisplay -v /dev/dsk/cntndn
For each of those logical volumes, you can use lvdisplay to check which logical
extents are mapped onto the disk, and if there’s a current copy of that data on
another disk:
lvdisplay -v /dev/vol_group/lvoln | grep /dev/dsk/cntndn
2. Back up the volume group configuration:
vgcfgbackup /dev/vol_group
3. If any of the logical volumes on the disk have a timeout assigned that isn’t the
default (zero), temporarily disable the timeout. For each logical volume:
lvchange -t 0 /dev/vol_group/lvoln
4. Temporarily disable all paths to the disk:
pvchange -a N /dev/dsk/cntndn
Managing Disks - Quick Reference Examples 111