Sun Cluster 3.1 Software Installation Guide

How to Create an md.tab File

Create an /etc/lvm/md.tab file on each node in the cluster. Use the md.tab file to define Solstice DiskSuite metadevices or Solaris Volume Manager volumes for the disksets you created.


Note –

If you are using local metadevices or volumes, ensure that local metadevices or volumes names are distinct from the device ID (DID) names used to form disksets. For example, if the DID name /dev/did/dsk/d3 is used in a diskset, do not use the name /dev/md/dsk/d3 for a local metadevice or volume. This requirement does not apply to shared metadevices or volumes, which use the naming convention /dev/md/setname/{r}dsk/d#.



Tip –

To avoid possible confusion between local metadevices or volumes in a cluster environment, use a naming scheme that makes each local metadevice or volume name unique throughout the cluster. For example, for node 1 choose names from d100-d199, for node 2 use d200-d299, and so on.


  1. Become superuser on the cluster node.

  2. List the DID mappings for reference when you create your md.tab file.

    Use the full DID pseudo-driver names in the md.tab file in place of the lower-level device names (cNtXdY).


    # scdidadm -L
    

    In the following example, the first column of output is the DID instance number, the second column is the full path (physical path), and the third column is the full DID pseudo-driver name (pseudo path).


    1       phys-schost-1:/dev/rdsk/c0t0d0 /dev/did/rdsk/d1
    2       phys-schost-1:/dev/rdsk/c1t1d0 /dev/did/rdsk/d2
    2       phys-schost-2:/dev/rdsk/c1t1d0 /dev/did/rdsk/d2
    3       phys-schost-1:/dev/rdsk/c1t2d0 /dev/did/rdsk/d3
    3       phys-schost-2:/dev/rdsk/c1t2d0 /dev/did/rdsk/d3
    ...

  3. Create an /etc/lvm/md.tab file and edit it by hand with your preferred text editor.

    See your Solstice DiskSuite/Solaris Volume Manager documentation and the md.tab(4) man page for details on how to create an md.tab file.


    Note –

    If you have existing data on the disks that will be used for the submirrors, you must back up the data before metadevice or volume setup and restore it onto the mirror.


  4. Activate the metadevices or volumes defined in the md.tab files.

    Go to How to Activate Metadevices or Volumes.

Example—Sample md.tab File

The following sample md.tab file defines the metadevices for the diskset named dg-schost-1. The ordering of lines in the md.tab file is not important.


dg-schost-1/d0 -t dg-schost-1/d1 dg-schost-1/d4
    dg-schost-1/d1 -m dg-schost-1/d2
        dg-schost-1/d2 1 1 /dev/did/rdsk/d1s4
        dg-schost-1/d3 1 1 /dev/did/rdsk/d55s4
    dg-schost-1/d4 -m dg-schost-1/d5
        dg-schost-1/d5 1 1 /dev/did/rdsk/d3s5
        dg-schost-1/d6 1 1 /dev/did/rdsk/d57s5

The sample md.tab file is constructed as follows.


Note –

The following example uses Solstice DiskSuite terminology. For Solaris Volume Manager, a trans metadevice is instead called a transactional volume and a metadevice is instead called a volume. Otherwise, the following process is valid for both volume managers.