How to Replace a Submirror

Before You Begin

Read Overview of Replacing and Enabling Components in RAID-1 and RAID-5 Volumes and Creating and Maintaining RAID-1 Volumes.

Steps

1. Make sure that you have root privilege and that you have a current backup of all data.

2. Use the metastat command to view the status of the RAID-1 volume and associated submirrors.

   # metastat mirror-name

3. Use one of the following methods to replace a submirror.

   • From the Enhanced Storage tool within the Solaris Management Console, open the Volumes node. Choose the mirror. Then, choose Action⇒Properties and click the Submirror tab. Follow the onscreen instructions. For more information, see the online help.

   • Use the metadetach, metaclear, metatinit, and metattach commands to replace an entire submirror.

     1. Use the metadetach command to the failed submirror from the mirror.

        # metadetach -f mirror-name submirror

        -f

        Forces the detach to occur

        mirror-name

        Specifies the name of the mirror

        submirror

        Specifies the submirror to detach

     2. Use the metaclear command to delete the submirror.

        # metaclear -f submirror

        -f

        Forces the deletion of the submirror to occur

        submirror

        Specifies the submirror to delete

     3. Use the metainit command to create a new submirror.

        # metainit volume-name number-of-stripes components-per-stripe component-name

        volume-name

        Specifies the name of the volume to create. For information on naming volumes, see Volume Names.

        number-of-stripes

        Specifies the number of stripes to create.

        components-per-stripe

        Specifies the number of components each stripe should have.

        component-names

        Specifies the names of the components that are used. This example uses the root slice, c0t0d0s0.

     4. Use the metattach command to attach the new submirror.

        # metattach mirror submirror

Example 11–19 Replacing a Submirror in a Mirror

The following example illustrates how to replace a submirror in an active mirror.

# metastat d20
d20: Mirror
    Submirror 0: d21
      State: Okay        
    Submirror 1: d22
      State: Needs maintenance
...
# metadetach -f d20 d22
d20: submirror d22 is detached
# metaclear -f d22
d22: Concat/Stripe is cleared
# metainit d22 2 1 c1t0d0s2 1 c1t0d1s2
d22: Concat/Stripe is setup
# metattach d20 d22
d20: components are attached

In this example, the metastat command confirms that the two-way mirror, d20, has a submirror, d22, in the “Needs maintenance” state. In this case, the entire submirror needs to be cleared and recreated. The metadetach command detaches the failed submirror from the mirror by using the -f option, which forces the detachment to occur. The metaclear command clears the submirror. The metainit command recreates submirror, d22, with new slices. Finally, the metattach command attaches the rebuilt submirror. A mirror resynchronization begins automatically.

The specific configuration of the new volume, d22, depends on the component you are replacing. A concatenation, as shown here, can sufficiently replace a concatenation. However, a concatenation would not be an ideal replacement for a stripe because it could impact performance.

You temporarily lose the capability for data redundancy while the mirror is a one-way mirror.