You may want to look at UV Replication using publisher/subscriber instead. If you have a transaction (update) that crosses the boundaries of one transaction log into the next, you will lose that transaction on the DR side. It is VERY likely - bordering on certain - that each transaction log will have this condition. When you use uvrolf (the rollforward program) to restore the tlogs on the DR box, when uvrolf sees the start of a transaction, but doesn't see the next log, it assumes that this is a failed transaction and drops it. Then, when the next log comes along, it sees the end of that dropped transaction as a failed transaction as well, and proceeds to restore the next transaction. The effect is random (you don't know which transaction will be the last one), and only shows up if you're looking for a transaction that dropped. Given 5Mb tlogs, and an average group size of 2K, you'd have a 99.95% chance of dropping the last transaction in each log, thereby losing 1 out of every 2500 updates.
I've thought about fixes, and it would probably work if you rolled forward each log twice, once when it comes over, and once when the next one comes over. You'd want to flip the flag back to have it show as not rolled forward so that you could do it the second time. You'd actually want to be sure to copy the original to another directory before running uvrolf against it, then copy it in again when the next log arrives. I think uvrolf keeps track of which log it expects next, and you'd have to decrement that (in more than one place, IIRC). It's a bit ugly, but it could work. I'm reminded of the Bugs Bunny where he gets stuck in Australia, and hitches a lift back in a kangaroo's pouch with the baby kangaroo. He's wearing a captain's hat, and starts barking orders: "Hoist the mizzenmast! Trim the sails! Batten down the hatches!". The baby kangaroo says, "But I already battened down the hatches". Bugs: "Batten 'em down again! We'll show them hatches!". -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of David Senecky Sent: Monday, March 30, 2009 6:06 PM To: [email protected] Subject: [U2] UniVerse and Transaction Logging Are there any known problems/issues/obstacles with UniVerse 10.2 & 10.3 and Transaction Logging on AIX 5.3?<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> I am looking for a DR solution using the above, are you using this? any tips / traps? David Disclaimer Notice This message contains privileged and confidential information intended only for the use of the addressee named above. If you are not the intended recipient of this message you are hereby notified that you must not disseminate, copy or take any action or place any reliance on it. If you have received this message in error please notify Ultradata immediately on +61 3 9291 1600. Any views expressed in this message are those of the individual sender, except where the sender specifically states them to be the views of Ultradata Australia Pty. Ltd. To unsubscribe from receiving commercial electronic messages from Ultradata Australia please email [email protected] with the subject heading "Unsubscribe". ------- u2-users mailing list [email protected] To unsubscribe please visit http://listserver.u2ug.org/ ------- u2-users mailing list [email protected] To unsubscribe please visit http://listserver.u2ug.org/
