Creating State Database Replicas

Caution - If you upgraded from the Solstice DiskSuite product to Solaris Volume Manager and you have state database replicas sharing slices with file systems or logical volumes (as opposed to on separate slices), do not delete existing replicas and replace them with new default replicas in the same location.

The default state database replica size in Solaris Volume Manager is 8192 blocks, while the default size in the Solstice DiskSuite product is 1034 blocks. Use caution if you delete a default-sized state database replica created in the Solstice DiskSuite product, and then add a new default-sized replica with Solaris Volume Manager. You will overwrite the first 7158 blocks of any file system that occupies the rest of the shared slice, thus destroying the data.

Caution - Do not place state database replicas on fabric-attached storage, SANs, or other storage that is not directly attached to the system. You might not be able to boot Solaris Volume Manager. Replicas must be on storage devices that are available at the same point in the boot process as traditional SCSI or IDE drives.

How to Create State Database Replicas

Before You Begin

Check Prerequisites for Creating Solaris Volume Manager Components.

Become superuser.
To create state database replicas, use one of the following methods:
- From the Enhanced Storage tool within the Solaris Management Console, open the State Database Replicas node. Choose Action⇒Create Replicas and follow the onscreen instructions. For more information, see the online help.
- Use the following form of the metadb command. See the metadb(1M).
```
# metadb -a -c number -l length-of replica -f ctds-of-slice
```
  -a
  
  Specifies to add or create a state database replica.
  
  -f
  
  Specifies to force the operation, even if no replicas exist. Use the -f to force the creation of the initial replicas.
  
  -c number
  
  Specifies the number of replicas to add to the specified slice.
  
  -l length-of-replica
  
  Specifies the size of the new replicas, in blocks. The default size is 8192. This size should be appropriate for virtually all configurations, including those configurations with thousands of logical volumes.
  
  ctds-of-slice
  
  Specifies the name of the component that will hold the replica.
Note - The metadb command entered on the command line without options reports the status of all state database replicas.

Example 7-1 Creating the First State Database Replica

# metadb -a -f c0t0d0s7
# metadb
        flags         first blk      block count
...
     a      u         16             8192            /dev/dsk/c0t0d0s7

You must use the -f option along with the -a option to create the first state database replica. The -a option adds state database replicas to the system.The -f option forces the creation of the first replica (and may be omitted when you add supplemental replicas to the system).

Example 7-2 Adding Two State Database Replicas to the Same Slice

# metadb -a -c 2 c1t3d0s1
# metadb
        flags         first blk      block count
...
     a        u         16              8192            /dev/dsk/c1t3d0s1
     a        u         8208            8192            /dev/dsk/c1t3d0s1

The -a option adds state database replicas to the system. The -c 2 option places two replicas on the specified slice. The metadb command checks that the replicas are active, as indicated by the a flag in the metadb command output.

Example 7-3 Adding State Database Replicas of a Specific Size

If you are replacing existing state database replicas, you might need to specify a replica size. Particularly if you have existing state database replicas (on a system upgraded from the Solstice DiskSuite product, perhaps) that share a slice with a file system, you must replace existing replicas with other replicas of the same size or add new replicas in a different location.

# metadb -a -c 3 -l 1034 c0t0d0s7
# metadb
        flags         first blk      block count
...
     a      u         16             1034            /dev/dsk/c0t0d0s7
     a      u         1050           1034            /dev/dsk/c0t0d0s7
     a      u         2084           1034            /dev/dsk/c0t0d0s7

The -a option adds state database replicas to the system. The -l option specifies the length in blocks of the replica to add.