HDR Primary and Secondary on different Versions

Hello, I have created a scenario where my HDR primary server is on IDS11.4FC3W1 where as HDR secondary server is on IDS11.5 FC4 and I am observing that replication is working fine. I have also tested it in reverse order with HDR primary is having 11.5FC4. It looks strange to me. As far as I know both versions should be same while setting up replication, but here in my case both are different. Does anybody know, whether its functionality of bug? Regards, Anees Ahmad

Hi, it is not said explicitly that HDR does not work at all with different versions for IDS. And (obviously) the non-functioning is not enforced by IDS. But what is said explicitly is that different versions of IDS are not supported for HDR. This means that if sometime in the future you run into a problem with your HDR configuration, then nobody will be able to help you. [ HDR is using the logical log records to implement replication. Sometimes the internal format of these logical log records changes between versions and new logical log records get added over time to support new functionality. Such new or changed log records cannot be supported by an older version of IDS. And since this is not supported, even the behaviour when encountering such a log record is in general unpredictable. It may "only" crash the system (then at least you'd know something bad happened). Worse, it may be interpreted wrongly and thus corrupt your data logically, but go otherwise unnoticed. In that case you'd have corrupted data without knowing about it. I would not trust even extensive testing, because I would not know for sure, that all the constellations of different log records have been covered enough by any test scenario. Therefore it is (I think) practically impossible to exclude the arrival of a "strange" log record sometime in the future. And therefore I would not run HDR with different versions of IDS - anyway not over a longer period of time. Rolling upgrades are in interesting topic, but not in the scope of this e-mail ... :-) ] Regards, Martin -- Martin Fuerderer IBM Informix Development Munich, Germany Information Management IBM Deutschland Research & Development GmbH Chairman of the Supervisory Board: Martin Jetter Board of Management: Erich Baier Corporate Seat: Boeblingen, Germany Reg.-Gericht: Amtsgericht Stuttgart, HRB 243294 ids-bounces@iiug.org wrote on 09.06.2009 08:16:36: > Hello, > > I have created a scenario where my HDR primary server is on IDS11. > 4FC3W1 where > as HDR secondary server is on IDS11.5 FC4 and I am observing that replication > is working fine. I have also tested it in reverse order with HDR primary is > having 11.5FC4. > It looks strange to me. As far as I know both versions should be same while > setting up replication, but here in my case both are different. > Does anybody know, whether its functionality of bug? > > Regards, > Anees Ahmad > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. >

It's a voodoo solution that you're using. Sometimes it might work, but= sometimes it might not. It all depends on 1) wheither a new log record= type is introduced and/or 2) whither we have to change the way log reco= rds are applied on the secondary. It is guarenteed that new log records an= d/or new formats of log records will exist between major releases and often = new log records are introduced with minor releases such as 11.50xC4 and 11.50xC5. I know for instance that there are new log records which hav= e been introduced as part of disk compression.... You are lucky that you have been able to make it work. Between 11.50xC= 3 and 11.50xC4 there were no additional log records introduced, but that = is not the case with every minor release (i.e. 11.50xC4 and 11.50xC5). If= you should run into a problem, however, you are not going to be able to rec= eive any support in resolving any issues. = "ANEES AHMAD" = <aanees@i2cinc.co = m> = To Sent by: ids@iiug.org = ids-bounces@iiug. = cc org = Subj= ect HDR Primary and Secondary on = 06/09/2009 01:16 different Versions [15973] = AM = = = Please respond to = ids@iiug.org = = = Hello, I have created a scenario where my HDR primary server is on IDS11.4FC3W= 1 where as HDR secondary server is on IDS11.5 FC4 and I am observing that replication is working fine. I have also tested it in reverse order with HDR primar= y is having 11.5FC4. It looks strange to me. As far as I know both versions should be same w= hile setting up replication, but here in my case both are different. Does anybody know, whether its functionality of bug? Regards, Anees Ahmad ***********************************************************************= ******** Forum Note: Use "Reply" to post a response in the discussion forum. =