SPARC: How to Mirror the Encapsulated Root Disk

After you install VxVM and encapsulate the root disk, perform this procedure on each node on which you mirror the encapsulated root disk.

1. Mirror the encapsulated root disk.

   Follow the procedures in your VxVM documentation. For maximum availability and simplified administration, use a local disk for the mirror. See Guidelines for Mirroring the Root Disk for additional guidelines.

   ---

   Caution –

   Do not use a quorum device to mirror a root disk. Using a quorum device to mirror a root disk might prevent the node from booting from the root-disk mirror under certain circumstances.

   ---

2. Display the DID mappings.

   # scdidadm -L

3. From the DID mappings, locate the disk that is used to mirror the root disk.

4. Extract the raw-disk device-group name from the device-ID name of the root-disk mirror.

   The name of the raw-disk device group follows the convention dsk/dN, where N is a number. In the following output, the portion of a scdidadm output line from which you extract the raw-disk device-group name is highlighted in bold.

   N node:/dev/rdsk/cNtXdY /dev/did/rdsk/dN

5. View the node list of the raw-disk device group.

   Output looks similar to the following.

   # scconf -pvv | grep dsk/dN Device group name: dsk/dN … (dsk/dN) Device group node list: phys-schost-1, phys-schost-3 …

6. If the node list contains more than one node name, remove from the node list all nodes except the node whose root disk you mirrored.

   Only the node whose root disk you mirrored should remain in the node list for the raw-disk device group.

   # scconf -r -D name=dsk/dN,nodelist=node

   -D name=dsk/dN

   Specifies the cluster-unique name of the raw-disk device group

   nodelist=node

   Specifies the name of the node or nodes to remove from the node list

7. Enable the localonly property of the raw-disk device group.

   When the localonly property is enabled, the raw-disk device group is used exclusively by the node in its node list. This usage prevents unintentional fencing of the node from its boot device if the boot device is connected to multiple nodes.

   # scconf -c -D name=dsk/dN,localonly=true

   For more information about the localonly property, see the scconf_dg_rawdisk(1M) man page.

8. Repeat this procedure for each node in the cluster whose encapsulated root disk you want to mirror.

9. Create disk groups.

   Go to SPARC: How to Create and Register a Disk Group.

SPARC: Example—Mirroring the Encapsulated Root Disk

The following example shows a mirror created of the root disk for the node phys-schost-1. The mirror is created on the disk c1t1d0, whose raw-disk device-group name is dsk/d2. Disk c1t1d0 is a multihost disk, so the node phys-schost-3 is removed from the disk's node list and the localonly property is enabled.

(Display the DID mappings)
# scdidadm -L 
…
2        phys-schost-1:/dev/rdsk/c1t1d0 /dev/did/rdsk/d2   
2        phys-schost-3:/dev/rdsk/c1t1d0 /dev/did/rdsk/d2   
…
 
(Display the node list of the mirror disk's raw-disk device group)
# scconf -pvv | grep dsk/d2
Device group name:						dsk/d2
…
  (dsk/d2) Device group node list:		phys-schost-1, phys-schost-3
…
 
(Remove phys-schost-3 from the node list)
# scconf -r -D name=dsk/d2,nodelist=phys-schost-3
  
(Enable the localonly property)
# scconf -c -D name=dsk/d2,localonly=true