Disaster Recovery using CA on XP256

[Andrew R.]

We already have a CA between 2 different sites with XP256 on each site,using SAP and Oracle application. I am wondering if anyone ever done the DR test using CA and horcm commands ?
So far I prepared some scripts running from cron to copy OS config. files from the Primary site to the DR site.
I'm more concern when after the DR is tested on the DR servers, How to go back to the primary server (horcmtakeover !!)

Any Tips /Recommendations are very much appreciated..Thanks a million

[Bernd Reize]

Hi Andrew,

as long as both XP's are online and can communicate with each other via the ESCON links, you can issue the horctakeover command without any problems.
There are two main cases for the command:
- local Vols are already PVOL(pair): no operation done
- local Vols are SVOL(pair): a swap-takeover is done.

All other states, i.e. 'suspended' or 'dubious' are in most cases error after a real disaster, for example. Normally, then you have manual work to do.

[Ovidiu D. Raita · Accepted solution]

In most of the cases you have one-way ESCON links (from prod to DR) and (depending on the RAID manager and XP FW) the prod XP might or might not know what S-VOL tracks were changed during the DR tests. If it doesn't you cannot do an incremental resync of the CA disks.

After the DR I would get all the disks in simplex mode (using pairsplit -l from both prod and DR sites) and then recreate the link from production (P-VOL) to DR (S-VOL) with paircreate. This will do a full resync of the disks and will prevent any data incosistency between prod and DR site.

This is the old-fashion way and it works fine.

I you have a newer FW have a look at the latest RAID Manager Users Guide http://www.hp.com/cposupport/manual_set/lpg28385.pdf

Regards,
Ovidiu