Responding to RAID 1 Volume Component Failures

How to Replace a Slice in a Submirror

Steps

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

2. Read Overview of Replacing and Enabling Components in RAID 1 and RAID 5 Volumes and Background Information for RAID 1 Volumes.

3. Use one of the following methods to replace a slice in a mirror.

   • From the Enhanced Storage tool within the Solaris Management Console, open the Volumes node, choose the mirror, then choose Action->Properties and click the Submirrors tab. Follow the instructions on screen. For more information, see the online help.

   • Use the following form of the metareplace command to replace a slice in a submirror:

     metareplace mirror-name component-name

     • mirror-name is the name of the volume to create.

     • component-name specifies the name of the component that is to be replaced.

     See the following examples and the metainit(1M) man page for more information.

Example 11–17 Replacing a Failed Slice in a Mirror

The following example illustrates how to replace a failed slice when the system is not configured to use hot spare pools for the automatic replacement of failed disks. See Chapter 16, Hot Spare Pools (Overview) for more information about using hot spare pools.

# metastat d6
d6: Mirror
    Submirror 0: d16
      State: Okay        
    Submirror 1: d26
      State: Needs maintenance
...
d26: Submirror of d6
    State: Needs maintenance
    Invoke: metareplace d6 c0t2d0s2 <new device>
...
# metareplace d6 c0t2d0s2 c0t2d2s2
d6: device c0t2d0s2 is replaced with c0t2d2s2

The metastat command confirms that mirror d6 has a submirror, d26, with a slice in the “Needs maintenance” state. The metareplace command replaces the slice as specified in the “Invoke” line of the metastat output with another available slice on the system. The system confirms that the slice is replaced, and starts resynchronizing the submirror.

How to Replace a Submirror

Steps

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

2. Read Overview of Replacing and Enabling Components in RAID 1 and RAID 5 Volumes and Background Information for RAID 1 Volumes.

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 Submirrors tab. Follow the instructions on screen. For more information, see the online help.

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

Example 11–18 Replacing a Submirror in a Mirror

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

The specific configuration of the new volume d22 will depend on the component you are replacing. A concatenation, as shown here, would be fine to replace a concatenation, but would not be an ideal replacement for a stripe as it could impact performance.

# 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

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 will be cleared and recreated. The metadetach command detaches the failed submirror from the mirror by using the -f option, which forces the detach to occur. The metaclear command clears the submirror. The metainit command recreates submirror d22, with new slices. The metattach command attaches the rebuilt submirror, and a mirror resynchronization begins automatically.

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