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Replacing a failed boot disk

The replacement disk for a failed boot disk must have at least as much storage capacity as was in use on the disk being replaced. It must be large enough to accommodate all subdisks of the original disk at their current disk offsets.

To estimate the size of the replacement disk, use this command:

# vxprint [-g diskgroup] -st -e 'sd_disk="diskname"'

where diskname is the name of the disk that failed or of one of its mirrors.

The following is sample output from running this command:

# vxprint -g rtdg -st -e 'sd_disk="rtdg01"'

Disk group: rtdg

SD NAME PLEX DISK DISKOFFS LENGTH [COL/]OFF DEVICE MODE

...

sd rtdg01-01 swapvol-01 rtdg01 0 1045296 0 c0t0d0 ENA

sd rtdg01-02 rootvol-01 rtdg01 1045296 16751952 0 c0t0d0 ENA

From the resulting output, add the DISKOFFS and LENGTH values for the last subdisk listed for the disk. This size is in 512-byte sectors. Divide this number by 2 for the size in kilobytes. In this example, the DISKOFFS and LENGTH values for the subdisk rtdg01-02 are 1,045,296 and 16,751,952, so the disk size is (1,045,296 + 16,751,952)/2, which equals 8,898,624 kilobytes or approximately 8.5 gigabytes.

  Note   Disk sizes reported by manufacturers usually represent the unformatted capacity of disks. Also, most manufacturers use the terms megabyte and gigabyte to mean a million (1,000,000) and a billion (1,000,000,000) bytes respectively, rather than the usual meaning of 1,048,576 and1,073,741,824 bytes.

To replace a failed boot disk:

1. Boot the system from an alternate boot disk.

   See "Booting from an alternate boot disks" on page 38.

2. Remove the association between the failing device and its disk name using the "Remove a disk for replacement" function of vxdiskadm.

   See the vxdiskadm (1M) manual page.

3. Shut down the system and replace the failed hardware.
4. After rebooting from the alternate boot disk, use the vxdiskadm "Replace a failed or removed disk" menu item to notify VxVM that you have replaced the failed disk.
   Warning: If the replacement disk was previously an encapsulated root disk under VxVM control, select to reorganize the disk when prompted. Otherwise, the disk is left with an invalid VTOC that renders the system unbootable. Ensure that you have made at least one valid copy of any existing data on the disk.
   
5. Use vxdiskadm to mirror the alternate boot disk to the replacement boot disk.
6. When the volumes on the boot disk have been restored, shut down the system, and test that the system can be booted from the replacement boot disk.