GPFS user exits
Apart from the user exits defined by using the mmaddcallback command, GPFS provides four more user exits: mmsdrbackup, nsddevices, syncfsconfig, and preunmount.
Table 1 summarizes the GPFS-specific user exits.
| User exit | Purpose |
|---|---|
| mmsdrbackup user exit | Performs a backup of the GPFS configuration data. |
| nsddevices user exit | Identifies local physical devices that are used as GPFS Network Shared Disks (NSDs). |
| syncfsconfig user exit | Keeps file system configuration data in replicated clusters synchronized. |
| preunmount user exit | Helps execute a clean shutdown of IBM Storage Scale when callbacks are not effective. |