Sun Cluster Software Installation Guide for Solaris OS

ProcedureHow to Set the Number of Metadevice or Volume Names and Disk Sets


Note –

Do not perform this procedure. in the following circumstances:


This procedure describes how to determine the number of Solstice DiskSuite metadevice or Solaris Volume Manager volume names and disk sets that are needed for your configuration. This procedure also describes how to modify the /kernel/drv/md.conf file to specify these numbers.


Tip –

The default number of metadevice or volume names per disk set is 128, but many configurations need more than the default. Increase this number before you implement a configuration, to save administration time later.

At the same time, keep the value of the nmdfield and the md_nsets field as low as possible. Memory structures exist for all possible devices as determined by nmdand md_nsets, even if you have not created those devices. For optimal performance, keep the value of nmd and md_nsets only slightly higher than the number of metadevices or volumes you plan to use.


Before You Begin

Have available the completed Disk Device Group Configurations Worksheet.

Steps
  1. Calculate the total number of disk sets that you expect to need in the cluster, then add one more disk set for private disk management.

    The cluster can have a maximum of 32 disk sets, 31 disk sets for general use plus one disk set for private disk management. The default number of disk sets is 4. You supply this value for the md_nsets field in Step 3.

  2. Calculate the largest metadevice or volume name that you expect to need for any disk set in the cluster.

    Each disk set can have a maximum of 8192 metadevice or volume names. You supply this value for the nmd field in Step 3.

    1. Determine the quantity of metadevice or volume names that you expect to need for each disk set.

      If you use local metadevices or volumes, ensure that each local metadevice or volume name on which a global-devices file system, /global/.devices/node@ nodeid, is mounted is unique throughout the cluster and does not use the same name as any device-ID name in the cluster.


      Tip –

      Choose a range of numbers to use exclusively for device-ID names and a range for each node to use exclusively for its local metadevice or volume names. For example, device-ID names might use the range from d1 to d100. Local metadevices or volumes on node 1 might use names in the range from d100 to d199. And local metadevices or volumes on node 2 might use d200 to d299.


    2. Calculate the highest of the metadevice or volume names that you expect to use in any disk set.

      The quantity of metadevice or volume names to set is based on the metadevice or volume name value rather than on the actual quantity . For example, if your metadevice or volume names range from d950 to d1000, Solstice DiskSuite or Solaris Volume Manager software requires that you set the value at 1000 names, not 50.

  3. On each node, become superuser and edit the /kernel/drv/md.conf file.


    Caution – Caution –

    All cluster nodes (or cluster pairs in the cluster-pair topology) must have identical /kernel/drv/md.conf files, regardless of the number of disk sets served by each node. Failure to follow this guideline can result in serious Solstice DiskSuite or Solaris Volume Manager errors and possible loss of data.


    1. Set the md_nsets field to the value that you determined in Step 1.

    2. Set the nmd field to the value that you determined in Step 2.

  4. On each node, perform a reconfiguration reboot.


    # touch /reconfigure
    # shutdown -g0 -y -i6
    

    Changes to the /kernel/drv/md.conf file become operative after you perform a reconfiguration reboot.

Next Steps

Create local state database replicas. Go to How to Create State Database Replicas.