Sun Cluster 3.0-3.1 Hardware Administration Manual for Solaris OS

Mirroring Internal Disks on Servers that Use Internal Hardware Disk Mirroring or Integrated Mirroring

Some servers support the mirroring of internal hard drives (internal hardware disk mirroring or integrated mirroring) to provide redundancy for node data. To use this feature in a cluster environment, follow the steps in this section.

Depending on the version of the Solaris operating system you use, you might need to install a patch to correct change request 5023670 and ensure the proper operation of internal mirroring. Check the PatchPro site to find the patch for your server.

The best way to set up hardware disk mirroring is to perform RAID configuration during cluster installation, before you configure multipathing. (For instructions on performing this configuration, see Chapter 1, Sun Cluster 3.1 8/05 Release Notes Supplement, in Sun Cluster 3.0-3.1 Release Notes Supplement.) If you need to change your mirroring configuration after you have established the cluster, you must perform some cluster-specific steps to clean up the device IDs.

Note –

Specific servers might have additional restrictions. See the documentation that shipped with your server hardware.

For specifics about how to configure your server's internal disk mirroring, refer to the documents that shipped with your server and the raidctl(1M) man page.

This section contains the following procedures:

How to Configure Internal Disk Mirroring After the Cluster is Established

Before You Begin

This procedure assumes that you have already installed your hardware and software and have established the cluster. To configure an internal disk mirror during cluster installation, see the Sun Cluster Installation Guide.

Check the PatchPro site for any patches required for using internal disk mirroring.

PatchPro is a patch-management tool that eases the selection and download of patches required for installation or maintenance of Sun Cluster software. PatchPro provides an Interactive Mode tool especially for Sun Cluster. The Interactive Tool makes the installation of patches easier. PatchPro's Expert Mode tool helps you to maintain your configuration with the latest set of patches. Expert Mode is especially useful for obtaining all of the latest patches, not just the high availability and security patches.

To access the PatchPro tool for Sun Cluster software, go to http://www.sun.com/PatchPro/, click Sun Cluster, then choose either Interactive Mode or Expert Mode. Follow the instructions in the PatchPro tool to describe your cluster configuration and download the patches.

For third-party firmware patches, see the SunSolve^SM Online site at http://sunsolve.ebay.sun.com.

If necessary, prepare the node for establishing the mirror.
1. Determine the resource groups and device groups that are running on the node.
  
  Record this information because you use this information in later in this procedure to return resource groups and device groups to the node.
  # scstat
2. If necessary, move all resource groups and device groups off the node.
  # scswitch -S -h fromnode

Configure the internal mirror.
# raidctl -c clt0d0 clt1d0
-c clt0d0 clt1d0

Creates the mirror of primary disk to the mirror disk. Enter the name of your primary disk as the first argument. Enter the name of the mirror disk as the second argument.

Boot the node into single user mode.
# reboot -- -S

Clean up the device IDs.
# scdidadm -R /dev/rdsk/clt0d0
-R /dev/rdsk/clt0d0

Updates the cluster's record of the device IDs for the primary disk. Enter the name of your primary disk as the argument.

Confirm that the mirror has been created and only the primary disk is visible to the cluster.
# scdidadm -l
The command lists only the primary disk as visible to the cluster.

Boot the node back into cluster mode.
# reboot

If you are using Solstice DiskSuite or Solaris Volume Manager and if the state database replicas are on the primary disk, recreate the state database replicas.
# metadb -afc 3 /dev/rdsk/clt0d0s4

If you moved device groups off the node in Step 1, move all device groups back to the node.

Perform the following step for each device group you want to return to the original node.
# scswitch -z -D devicegroup -h nodename
In these commands, devicegroup is one or more device groups that are returned to the node.

If you moved resource groups off the node in Step 1, move all resource groups back to the node.
# scswitch -z -g resourcegroup -h nodename

How to Remove an Internal Disk Mirror

If necessary, prepare the node for removing the mirror.
1. Determine the resource groups and device groups that are running on the node.
  
  Record this information because you use this information later in this procedure to return resource groups and device groups to the node.
  # scstat
2. If necessary, move all resource groups and device groups off the node.
  # scswitch -S -h fromnode

Remove the internal mirror.
# raidctl -d clt0d0
-d clt0d0

Deletes the mirror of primary disk to the mirror disk. Enter the name of your primary disk as the argument.

Boot the node into single user mode.
# reboot -- -S

Clean up the device IDs.
# scdidadm -R /dev/rdsk/clt0d0 # scdidadm -R /dev/rdsk/clt1d0
-R /dev/rdsk/clt0d0
-R /dev/rdsk/clt1d0

Updates the cluster's record of the device IDs. Enter the names of your disks separated by spaces.

Confirm that the mirror has been deleted and that both disks are visible.
# scdidadm -l
The command lists both disks as visible to the cluster.

Boot the node back into cluster mode.
# reboot

If you are using Solstice DiskSuite or Solaris Volume Manager and if the state database replicas are on the primary disk, recreate the state database replicas.
# metadb -c 3 -ag /dev/rdsk/clt0d0s4

If you moved device groups off the node in Step 1, return the device groups to the original node.
# scswitch -z -D devicegroup -h nodename

If you moved resource groups off the node in Step 1, return the resource groups and device groups to the original node.
# scswitch -z -g resourcegroup -h nodename