RE: Using Replication
Posted in 2000
If you mean High-availability Data Replication (HDR), then, yes, we are
using it.
Primary and secondary servers are located several hundred miles apart,
communicating over a very busy T1. DRINTERVAL is set to 30, but almost
everything is replicated within a few seconds. We use asynchronous because
we don't want to impact the primary -- user response time on that machine is
critical. We leave DRAUTO at 0 (manual switchover), because we have been
told that (1) you can get a lot of unnecessary switching if you have
occasional minor network "blips", and (2) under some circumstances, it might
be possible for the secondary to switch itself to primary, and yet the old
primary does NOT switch to secondary, so you can have users making possibly
conflicting updates to both boxes -- major nightmare! Perhaps for these
reasons (I don't know for sure why), HDR in IDS.2000 does not have the
DRAUTO option configurable -- it is "hard-coded" to 0 (manual). And this
has not really been a problem for us. Whenever we need to do maintenance on
the primary box (this is a critical 24x7 application), we've got the
switchover routine down to about a minute. The most time-consuming part is
*nicely* getting the user sessions off of the old primary. If it's an
emergency, an "onmode -uy" does the trick quickly. :-) Then I just advance
to the next logical log a couple of times (forces flush to secondary), force
a checkpoint, change the primary to "standard" mode, and then bring it down.
Then I switch the secondary to "standard" mode, and the users can start
connecting to it now.
The biggest reasons that I really like HDR are (1) very low maintenance, (2)
reliable and resilient (replication almost always restarts and
re-synchronizes automatically after network problems), and (3) very easy and
straightforward to setup / restart.
HTH,
Paul Mosser
Wells Fargo & Co.
-----Original Message-----
From: SongIn_Lindsey@frankel.com [mailto:SongIn_Lindsey@frankel.com]
Sent: Friday, September 08, 2000 3:04 PM
To: informix-list@iiug.org
Subject: Using Replication
Is any one using replication in their environment? Looking for feedback.
If you are, please give some experiences and details of your environmental
setting that is being used in your replication environment. How is
performance on the primary servers, what DRINTERVAL used, what setting for
DRAUTO is being used, etc.
Thank you,
Send email to SongIn_Lindsey@frankel.com