In the past, if you had a fully duplicated system, you had to have all prime modules online in order to run z/TPF capture (ZFCAP).  Also, if a prime module was down, you could not restore your system nor could you restore to a duplicate module even if your system was fully duplicated.

With PJ41914, this is changed.  If your system is fully duplicated, then you do not have to have all the prime modules online in order to capture the database.  z/TPF capture will capture the dupe modules in place of any prime modules which are offline.  Also, in the event that you do a restore in a fully duplicated environment, as long as one of the prime or dupe of every module is online, you may restore your database as well as restore an individual module.

To understand how this works, consider a few simple scenarios.

(1) If your database is fully duplicated, and some of your prime modules are offline, as long as the corresponding dupe modules are online, you may capture your database.
(2) When running restore, if the prime modules are offline but the dupe modules are online, you may restore your system.  
(3) When running restore, if there are prime modules that were online during capture, but are now offline, you may still restore your system provided that the corresponding dupe modules are online.
In a fully duplicated environment, z/TPF will simply use the tapes that were used to capture the prime modules, and restore them to the corresponding duplicate modules.  This is true for restore of all modules as well as restore of individual modules.
(4) When running restore, if there were prime modules that were offline during the capture, and the dupes were captured in their place, you may still restore your system (or those individual modules) even if those prime modules are now online.  (z/TPF will simply use tapes that were used to capture duplicate modules to restore the corresponding prime modules in a fully duplicated environment.)

These are just some of the scenarios which are now handled by capture and restore, to give you a better idea of how capture and restore now handle fully duplicated environments.  Please note that these enhancements apply whether you use prime/dupe mod pairing or IBM standard module pairing.

We strongly recommend you install PJ41914 on your system if you use capture and/or restore because in addition to making the enhancements described above, this APAR also corrects some base problems with capture/restore even in environments which are not fully duplicated.  For additional details, please refer to the APEDIT which may be found at this link:

 http://www-01.ibm.com/support/docview.wss?uid=swg1PJ41914

 We hope you find these enhancements to capture and restore useful.  If you have any questions, please feel free to contact your CSR or comment on this blog entry and I will answer your question.