Replacing defective disks when the cluster is offline


Replacing defective disks when the cluster is offline
Prev	Troubleshooting I/O fencing	Next

If the disk in the coordinator disk group becomes defective or inoperable and you want to switch to a new diskgroup in a cluster that is offline, then perform the following procedure.

In a cluster that is online, you can replace the disks using the vxfenswap utility.

See About the vxfenswap utility.

Review the following information to replace coordinator disk in the coordinator disk group, or to destroy a coordinator disk group.

Note the following about the procedure:

When you add a disk, add the disk to the disk group vxfencoorddg and retest the group for support of SCSI-3 persistent reservations.
You can destroy the coordinator disk group such that no registration keys remain on the disks. The disks can then be used elsewhere.

To replace a disk in the coordinator disk group when the cluster is offline

Log in as superuser on one of the cluster nodes.
If VCS is running, shut it down:
```
# hastop -all
```
Make sure that the port h is closed on all the nodes. Run the following command to verify that the port h is closed:
```
# gabconfig -a
```
Stop I/O fencing on each node:
```
# /etc/init.d/vxfen.rc stop
```
This removes any registration keys on the disks.
Import the coordinator disk group. The file /etc/vxfendg includes the name of the disk group (typically, vxfencoorddg) that contains the coordinator disks, so use the command:
```
# vxdg -tfC import 'cat /etc/vxfendg'
```
where:

-t specifies that the disk group is imported only until the node restarts.

-f specifies that the import is to be done forcibly, which is necessary if one or more disks is not accessible.

-C specifies that any import locks are removed.
To remove disks from the disk group, use the VxVM disk administrator utility, vxdiskadm.
You may also destroy the existing coordinator disk group. For example:
- Verify whether the coordinator attribute is set to on.
```
# vxdg list vxfencoorddg |  grep flags: | grep coordinator
```
- Destroy the coordinator disk group.
```
# vxdg -o coordinator destroy vxfencoorddg
```
Add the new disk to the node and initialize it as a VxVM disk.
Then, add the new disk to the vxfencoorddg disk group:
- If you destroyed the disk group in step 5, then create the disk group again and add the new disk to it.
  
  See the Cluster Server Installation Guide for detailed instructions.
- If the diskgroup already exists, then add the new disk to it.
```
# vxdg -g vxfencoorddg -o coordinator adddisk disk_name
```
Test the recreated disk group for SCSI-3 persistent reservations compliance.
See Testing the coordinator disk group using the -c option of vxfentsthdw.
After replacing disks in a coordinator disk group, deport the disk group:
```
# vxdg deport 'cat /etc/vxfendg'
```
On each node, start the I/O fencing driver:
```
# /etc/init.d/vxfen.rc start
```
Verify that the I/O fencing module has started and is enabled.
```
# gabconfig -a
```
Make sure that port b membership exists in the output for all nodes in the cluster.
```
# vxfenadm -d
```
Make sure that I/O fencing mode is not disabled in the output.
If necessary, restart VCS on each node:
```
# hastart
```

Prev	Up	Next
Registered keys are lost on the coordinator disks	Home	The vxfenswap utility exits if rcp or scp commands are not functional