How to Set the Number of Metadevice or Volume Names and Disksets

If you used SunPlex Manager to install Solstice DiskSuite software, do not perform this procedure. Instead, go to Mirroring the Root Disk.

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

The default number of metadevice or volume names per diskset 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.

1. Have available the Disk Device Group Configurations Worksheet.

2. Determine the total number of disksets you expect to need in the cluster, then add one more diskset for private disk management.

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

3. Determine the largest metadevice or volume name you expect to need for any diskset in the cluster.

   Each diskset can have a maximum of 8192 metadevice or volume names. You supply this value for the nmd field in Step 4.

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

      If you use local metadevices or volumes, ensure that each local metadevice or volume name is unique throughout the cluster and does not use the same name as any device-ID name in the cluster.

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      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.

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   2. Determine the highest of the metadevice or volume names you expect to use in any diskset.

      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/Solaris Volume Manager software requires that you set the value at 1000 names, not 50.

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

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   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 disksets served by each node. Failure to follow this guideline can result in serious Solstice DiskSuite/Solaris Volume Manager errors and possible loss of data.

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   1. Set the md_nsets field to the value that was determined in Step 2.

   2. Set the nmd field to the value that was determined in Step 3.

5. 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.

6. Create local state database replicas.

   Go to How to Create State Database Replicas.