[EMAIL PROTECTED] wrote: > My apologies. I forgot to post what we're currently running: UniData > 5.2.28-64 on HP-UX 11.11. > > We're currently on an upgrade path to take us to 6.1.10 in the near > future. Since DR was new with 6.0, we'll now be able to take > advantage > of the DR capabilities as you suggested. We're looking into that now. > > The comments I've received regarding journaling have warned us to stay > away from it as it is old technology and doesn't scale well. DR has > been recommended, but we have the same questions as we did for > journaling, particularly around performance and scalability. > Perhaps I > should repost the questions. :-) > > Thank you for your comments. It's good to hear positive > things about a relatively new function.
Dean, I just want to clear up what looks like a little bit of confusion. I mentioned replication as a UniData built-in, but I have no direct experience of that myself. I believe there were a few folk on this list looking at that when it first came out, I don't recall anyone either screaming about how useless it was, or raving about its wonders. A re-post of your question might well elicit some useful feedback. What I meant to point out was that it is possible (if you know what you are doing) to use UniData's RFS which has been around since 4.1 IIRC to implement a Disaster Recovery strategy (what I meant by DR). UniData do not document this as an option, but so long as you can keep the pathnames the same between production and DR servers, there is no problem with copying the RFS archive logs across from one machine to the other and using mediarec to do a rollforward. I have this configured to run automatically for my client and every 15 minutes the current archive log is copied over the net, while every night, after the backup is completed it is also copied across the network and automatically restored onto the DR machine. Thus at start of business each day the production and DR boxes have synchronised databases and in the event of a catastrophic failure of the production machine all that is needed is a shutdown of UniData on the DR box and a mediarec to bring it up to the minute with transactions from todays archive logs which will, at most be 15 minutes out of date. Obviously this isn't ideal, but it is far better than having to go back to a backup, and the benefit of having the DR box up and available for reporting purposes every day outweighs the delay involved with taking it back down again to do a rollforward if a failure occurs. To be honest, my experience is that on the occasions when we have had to do such failovers, the delay in getting the systems people to acknowledge that the primary machine is not going to be back anytime soon is longer than the delay getting the secondary machine online as its replacement. Anyhow, my experience with RFS is that it is very resilient and scaleable, with little impact on performance for online enquiries and transactions except the use of a little more memory, but some noticeable impact on batch IO performance (maybe an extra 50% on the time taken to run my clients end of day bulk updating procedures if they do those with RFS switched on). HTH, Ken > Ken Wallis wrote: > > I've only ever looked at Journaling as a poor-man's RFS. In > > that capacity it really didn't cut the mustard. > > > > I have, however, successfully set up RFS for use in a DR > > scenario - archive logs regularly and automatically copied to > > a backup machine and replayed there automatically each > > morning via mediarec. This is running well at decent sized > > production site, but nothing like the user population you are > > talking about - 100 to 150 users, not 1000 like you have. > > > > In an ideal world, IBM would publish the format of the > > archive logs so one could write a tool to allow transactions > > to be picked out of these and replayed over to a remote > > system without stopping it and doing a mediarec rollforward, > > but with UniData having replication built-in using an > > entirely different approach, I doubt they'll ever allow that. > > > > Do you have version issues which would prevent you using > > replication for this purpose Dean, or have you identified > > issues that prevent it from working for you? ------- u2-users mailing list [email protected] To unsubscribe please visit http://listserver.u2ug.org/
