Failback with temporary loss and no configuration changes

If the outage was of a temporary nature and your configuration has not been altered, it is a simple process to fail back to the original state.

After all affected nodes and disks have been repaired and you are certain the data on the failed disks has not been changed:

Start GPFS on the repaired nodes where the file gpfs.sitesAC lists all of the nodes at sites A and C:
```
mmstartup -N gpfs.sitesAC
```
Restart the affected disks. If more than one disk in the file system is down, they must all be started at the same time:
```
mmchdisk fs0 start -a
```