I have a call manager cluster with 3 servers(1 PUB + 2 SUB) running on 4.1(3). I am planning to upgrade to 6.1(3). I want to do PUB upgrade first. During the time when PUB is getting upgraded to 6.1(3) using DMA, call processing will be taken care of by other 2 SUB servers. If the upgrade of PUB fails the I want to revert to 4.1(3). Using disaster recovery disc, I can choose the windows pre install option to re-install. At this stage will the PUB pull the config from other 2 SUB servers or do I need to restore the old backup.
if you have to roll back then you'll have to restore from backup, the Publisher won't pull the database from the Subscribers. The following document details your upgrade steps and has a section on reverting to previous versions in the case of failure.
Thanks for your reply. I have backup of all 3 servers in a single file and also backup of PUB alone using BARS. Should I restore the entire backup or is it sufficient if I restore the backup of PUB alone when upgrade fails.
If the upgrade were to fail before you changed the subscribers you'd restore the Publisher only from the BARS backup you have. The subscribers won't need to be restored.
If the upgrade were to fail before Subscribers are upgraded, then should I restore:
1) backup file of PUB alone
2) backup file that has all 3 servers backup info.
on the PUB server.
If it is possible I would suggest upgrading one of your subscribers to the new CM6 Publisher and let the CM4 Pub look after call control of that SUB. This has worked well with me and if there are any issues and you need to roll back you can do a clean install on the Sub and reintergrate to the CM4 Pub with no backup/restore required of the PUB.
apologies if my previous answer wasn't clear. Option 1 from your list above, backup file of the Pub alone.
I would recommend taking a backup of the Publisher just before performing the upgrade so you have the most recent version of the database.