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Sun Cluster 3.0 5/02 Supplement

How to Create a Diskset (5/02)

The following change was introduced in the Sun Cluster 3.0 5/02 update release and applies to this update and all subsequent updates to Sun Cluster 3.0 software.

Perform this procedure for each diskset you create.

only -

If you used SunPlex Manager to install Solstice DiskSuite, one to three disksets might already exist. See "Using SunPlex Manager to Install Sun Cluster Software (5/02)" for information about the metasets created by SunPlex Manager.

  1. Do you intend to create more than three disksets in the cluster?

    • If yes, go to Step 2 to prepare the cluster for more than three disksets. Do this regardless of whether you are installing disksets for the first time or you are adding more disksets to a fully configured cluster.

    • If no, go to Step 6.

  2. Ensure that the value of the md_nsets variable is set high enough to accommodate the total number of disksets you intend to create in the cluster.

    1. On any node of the cluster, check the value of the md_nsets variable in the /kernel/drv/md.conf file.

    2. If the total number of disksets in the cluster will be greater than the existing value of md_nsets minus one, on each node increase the value of md_nsets to the desired value.

      The maximum permissible number of disksets is one less than the value of md_nsets. The maximum possible value of md_nsets is 32.

    3. Ensure that the /kernel/drv/md.conf file is identical on each node of the cluster.

      Caution - Caution -

      Failure to follow this guideline can result in serious Solstice DiskSuite errors and possible loss of data.

    4. From one node, shut down the cluster.


      # scshutdown -g0 -y

    5. Reboot each node of the cluster.


      ok> boot

  3. On each node in the cluster, run the devfsadm(1M) command.

    You can run this command on all nodes in the cluster at the same time.

  4. From one node of the cluster, run the scgdevs(1M) command.

  5. On each node, verify that the scgdevs command has completed before you attempt to create any disksets.

    The scgdevs command calls itself remotely on all nodes, even when the command is run from just one node. To determine whether the scgdevs command has completed processing, run the following command on each node of the cluster. 


    % ps -ef | grep scgdevs

  6. Ensure that the diskset you intend to create meets one of the following requirements.

    • If configured with exactly two disk strings, the diskset must connect to exactly two nodes and use exactly two mediator hosts, which must be the same two hosts used for the diskset. See "Mediators Overview" in the Sun Cluster 3.0 12/01 Software Installation Guide for details on how to set up mediators.

    • If configured with more than two disk strings, ensure that for any two disk strings S1 and S2, the sum of the number of disks on those strings exceeds the number of disks on the third string S3. Stated as a formula, the requirement is that count(S1) + count(S2) > count(S3).

  7. Ensure that root is a member of group 14. 


    # vi /etc/group
...
sysadmin::14:root
...

  8. Ensure that the local metadevice state database replicas exist.

    For instructions, see "How to Create Metadevice State Database Replicas" in the Sun Cluster 3.0 12/01 Software Installation Guide.

  9. Become superuser on the cluster node that will master the diskset.

  10. Create the diskset.

    This command also registers the diskset as a Sun Cluster disk device group.


    # metaset -s setname -a -h node1 node2
    -s setname

    Specifies the diskset name

    -a

    Adds (creates) the diskset

    -h node1

    Specifies the name of the primary node to master the diskset

    node2

    Specifies the name of the secondary node to master the diskset

  11. Verify the status of the new diskset.


    # metaset -s setname

  12. Add drives to the diskset.

    Go to "Adding Drives to a Diskset" in the Sun Cluster 3.0 12/01 Software Installation Guide.

Example-Creating a Diskset

The following command creates two disksets, dg-schost-1 and dg-schost-2, with the nodes phys-schost-1 and phys-schost-2 assigned as the potential primaries.


# metaset -s dg-schost-1 -a -h phys-schost-1 phys-schost-2
# metaset -s dg-schost-2 -a -h phys-schost-1 phys-schost-2