NetWorker: Implementing Tape Device Name Persistence for Windows

Tape Devices in NetWorker are configured with the driver name the Operating System has assigned them when they are first detected and configured by NetWorker.

Several events may cause the Operating System to change the devices' names: Host or device reboot, temporary connectivity loss, SAN reconfiguration, and others.

In order to ensure your Windows NetWorker Storage Nodes or Server retains a valid name for all zoned tape devices, Persistence must be configured in the Operating System.

There are two different and supported methods which may be used, depending on the driver installed. You can locate the driver by going into the properties of the devices in Device Manager, and checking the filename under the Driver tab, and Driver Details button.

IBM driver (ibmtp2k*)

1. Open the registry with regedit command
2. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\ibmtp2k*
3. Create a DWORD value (case sensitive): PersistentNaming with value of 1

All other drivers

1. Open the registry with regedit command
2. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Tape
3. Create a DWORD value (case sensitive): Persistence with value of 1

When this is complete - run inquire -slc and confirm that the Tape devices now show a longer name (for example instead of \\.\Tape0, now akin to \\.\Tape21474056 so forth)

Next actions

1. Open Device Manager using devmgmt.msc and disable then reenable all tape devices
2. In NMC you have two choices:
   1. Reconfiguration preserving existing Library instance (preserves existing Library settings)
      • Right-click and Reconfigure Library instance
      • Clear all but one device, then click Configure
      • Delete the orphaned Tape device instances from the Devices container
      • Scan for devices for the affected Nodes to rediscover new Tape device names
      • Reconfigure Library, checking all new Tape device instances, and clearing the remaining Tape - then select Configure
      • Finally, delete that last Tape's instance from Devices and rescan/reconfigure a second time, this time adding the last device
   2. Full library recreation (review specific configuration items before, like Cleaning, Features, Timers, Auto Media Management, so forth)
      • Delete Library instance, and all Tape devices belonging to that instances afterward, from the Devices container
      • Scan for devices for the affected Node to rediscover new device names
      • Reconfigure Library, checking all new instances, and select Configure
      • After completion, ensure any Library configuration details required are replaced, like Cleaning Tape, Features or Timers changes, so forth

From this point on - you should no longer need to worry about tape device names changing below the application layer, invalidating the names configured in NetWorker.

• udev is the equivalent Persistent Naming package installable to Linux
• HP-UX, Solaris, and AIX tape devices are all configured persistently to begin with and do not require these measures
• This does NOT prevent connectivity loss to devices, but ensures name consistency
• Protection does not extend to the tape or robot SCSI addresses: Because we use the SCSI address for the changer, the Library is still affected if the SCSI address changes.