The Backstore Engine › USS Backstore › File System Reconfiguration

File System Reconfiguration

Once the USS Backstore file system has been setup there should be little need to make changes to the configuration. However, should the need arise we recommend careful planning and to implementing file system changes during periods of low activity.

The underlying approach is to insure the IO Engine disk cache has enough capacity to tolerate suspending Externalization to the USS file systems and that applications requiring recalls tolerate mount pending for the time during the outage.

We recommend you implement Backstore Primary and Failover servers as described in section Configuring the Backstore Engine in Primary and Failover Roles.

To implement file systems changes

1. Prevent scratch synchronization jobs from running during the reconfiguration.
2. Shutdown any non-essential CA Vtape subsystems.
3. For each active CA Vtape subsystem in the CA Vtape Complex do the following:
   • Issue SVTS D G and note the current Max drives and USS settings
   • Issue SVTS SET MAXUSS=0
   • Issue SVTS SET MAXDRIVES=0
4. Make changes to the VUSSMNTS parmlib member to reflect the desired configuration changes.
5. For each active CA Vtape subsystem in the CA Vtape Complex do the following:
   • Issue SVTS REFRESH=USS
   • Reply Y to activate the parmlib changes

   At this point the new file system configuration is active but some of the Virtual Volume files are unavailable.

6. Copy the files from the original directories to the new directories.

   This can be done by mounting the original directories to temporary mount points and then copy to the new directory.

7. For each active CA Vtape subsystem in the CA Vtape Complex reset the Max drives and USS to the original settings noted in step 3.
   • Issue SVTS SET MAXUSS=n
   • Issue SVTS SET MAXDRIVES=n