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FDRPAS Technical Description

An FDRPAS “swap” of a disk volume is very simple.

A monitor job or task is started on each z/OS system that has access to the volumes to be swapped. Then, a simple FDRPAS job is started (or a console command issued) to request that an online volume be swapped to an offline disk device.

The swap of a volume can be initiated on any system in the complex, and the other systems will automatically join in the swap operation. FDRPAS will verify that the target device is offline to all sharing systems, to insure that an active volume cannot be accidentally overlaid.

For each requested volume, FDRPAS will copy all allocated tracks on the volume to the new disk device (for inactive data sets, only used tracks are copied), while simultaneously detecting all updates to the original device; updated tracks will be re-copied if necessary. The new device remains offline during the copy, so that the copied data is protected until the swap is complete.

Once the copy is completed, FDRPAS will swap the devices so that all I/O is now directed to the new device and the old device is no longer in use. The new device is placed online and the old device is offline. The old device will be modified so that z/OS will no longer be able to vary it online. When the system is re-IPLed, the new device will automatically come online.

Only the source and target devices are accessed by FDRPAS. It does not use any additional communication between systems, and it does not require TCP/IP, VTAM, a data set on a third disk volume or a coupling facility.

Swapping of a volume can be terminated at any time before the final swap without affecting the original device or any applications using it.

When all volumes in an old disk subsystem have been swapped to new disks, the old subsystem can be disconnected and removed.

Command Examples & Sample Output

On a single system, a console command like the one shown here can be used to initiate an FDRPAS swap:
S PASPROC.PROD01,PARM='SWAP TYPE= FULL/MOUNT VOL=PROD01,SWAPUNIT=25C0'
On multiple systems, prior to issuing the SWAP command, you start an FDRPAS monitor task for the potential FDRPAS target devices on each system with a console command like this:
S PASPROC.MON1,PARM='MONITOR TYPE=SWAP/MOUNT SWAPUNIT=(25C*,3*)'
The following sample output shows the swap of a TSO volume shared by 10 systems. Users and applications were accessing the volume on all of the systems. The swap took place simultaneously on all 10 systems and was completed in 6.5 minutes.

ISPF Monitoring Panels

FDRPAS ISPF panels allow you to display volumes by volser, unit, storage group, controller serial number or subsystem ID. You can initiate FDRPAS swaps, monitor their progress, change pacing values dynamically, and (if required) terminate swaps. Multiple display formats are available.

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