Reverting Source DB to Replication Target

Posted by James Palmer on 25-Apr-2014 03:27

Morning all. We had a catastrophic failure of our production database last night. Possibly a disk failure. Unfortunately it happened before the nightly backups kicked in, so the backups are a day old. 

More fortunately, the replication target seems to be error free. We are looking at the possibility of reverting to the replication target. I've found this guide for how to transition the target - http://knowledgebase.progress.com/articles/Article/P121084 but I'm wondering, what would I do to get this on to the source host? Is it a simple case of backing it up, and then restoring on the source? 

Obviously this assumes the hardware failure on the source host is fixed which is currently being attended to. 

OE 11.2.1

Thanks folks.

All Replies

Posted by Paul Koufalis on 25-Apr-2014 07:13

To get a copy of the tgt back on the primary server, just backup, transfer and restore. The restored DB on the primary server will be enabled as a replication tgt so disable it using proutil db -C disablesitereplication target. Then you'll have to go through the whole resync process.

The better option would have been to have configured and tested failover + fail back. You could have started up production on the secondary server, then when the primary was back online, started replicating back to the primary (primary would be the tgt). Eventually, with a down time of just a few minutes, you could have reversed the roles back to the normal prod/primary and DR/secondary.

Posted by James Palmer on 25-Apr-2014 07:48

Thanks Paul. Yes I agree we should have tested the scenarios for this in advance. It will be high on my list of priorities for the future.

Thanks for confirming what I needed to know though :)

Posted by Paul Koufalis on 25-Apr-2014 08:00

You really, really, REALLY should come to my High Availability Hands-On Workshop in Westford MA in June. The students get to configure and test ALL the interesting OE Replication scenarios using their own Amazon Linux instances. Really, you DO it all.  In the second half of the workshop, you will setup and test HA for AppServers and the NameServer.  It is a very cool workshop (if I do say so myself).

Heck, for you, the cost of the whole conference (maybe $1500 including flight, conference registration, hotel and miscellaneous) is justifiable JUST to attend this workshop.  

Posted by James Palmer on 25-Apr-2014 08:14

It sounds awesome! I will pass on your recommendations!!

Posted by ChUIMonster on 25-Apr-2014 08:19

Paul is absolutely correct -- that workshop is really good, I sat in on it in Brussels.

pugchallenge.org/register.html  -- it's a bargain even at twice the price :)

Posted by gus on 25-Apr-2014 13:17

I peeked in on it too. It was excellent. Highly recommended.

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