Re: ontape: bad performance
Tarcisio Gouveia said: > Recently we changed the hardware, OS and db version. > > INFORMIX7.31.FC6X2 DEC-UNIX4.0E to INFORMIX7.31.FD2X2 OSF1 V5.1 > > After the change, the backup time was very good taking 3 hours for 500 GB > in > a HP STORAGEWORKS ULTRIUM drive. > Any days later the performance degradated, now it takes aproximately 4 > days > during the week, and 2 days at weekend. > > Where can be the problem ? Well, it could be the hardware, OS or db version. -- Bye now, Obnoxio "C'est pas parce qu'on n'a rien ' dire qu'il faut fermer sa gueule" - Coluche "I'm trying to see things your way, but I can't get my head up my ass" - JCH "Ogni uomo mi guarda come se fossi una testa di cazzo" - Marco Travel broadens a person. You look as if you have been all over the world. I went to the airport to check in and they asked what I did because I looked like a terrorist. I said I was a comedian. They said, "Say something funny then." I told them I had just graduated from flying school. -- Ahmed Ahmed http://i2.photobucket.com/albums/y41/Obnoxio/thinkIfoundtheproblem.jpg sending to informix-list
Obnoxio The Chav wrote: > Tarcisio Gouveia said: >>Recently we changed the hardware, OS and db version. >> >>INFORMIX7.31.FC6X2 DEC-UNIX4.0E to INFORMIX7.31.FD2X2 OSF1 V5.1 >> >> After the change, the backup time was very good taking 3 hours for >> 500 GB in a HP STORAGEWORKS ULTRIUM drive. Any days later the >> performance degradated, now it takes aproximately 4 days during the >> week, and 2 days at weekend. >> >>Where can be the problem ? > > Well, it could be the hardware, OS or db version. And, if the trouble is in the DBMS rather than the OS or HW, it could, conceivably, be the very old archive page problem... I think the current version of IDS 7.31 should be FD6, not FD2 (though FD2 should be better than the previous FC6). Check the performance of the storage system without involving IDS. If that is running slow, you've reduced the problem to one of the OS or the HW. If that runs fast, you've probably reduced the problem to the DB. -- Jonathan Leffler #include <disclaimer.h> Email: jleffler@earthlink.net, jleffler@us.ibm.com Guardian of DBD::Informix v2005.01 -- http://dbi.perl.org/
We had similar performance losses at several customer sites following the upgrade from 7.31.xC6 to 7.31.xD2. What we noticed as the critical symptom were increasing checkpoint lengths, until one site was averaging 18,000 seconds per checkpoint. This affected performance everywhere, but usually occurred during backups. It turned out that we were running into one of the side-effects of the fix to the arc_very_old_page bug (101062). One recommendation we tried was setting the following ONCONFIG parameter before bringing the engine online: CCFLAGS 0x400000 This gave us limited relief, as checkpoints dropped down to minutes, but, most importantly, it helped Informix support identify the problem. We were running into IDS bugs 150991 which is a result of the fix for bug 145675 which is a result of the fix for bug 101062. To make a long story short, we had to upgrade our customers to the 7.31.xC4 release to get past all traces of 101062, then set CCFLAGS, and turn off KAIO on AIX platforms. Here are a couple of IBM links for info on 101062 & CCFLAGS. I will warn you that IBM's website is less user friendly than the surlier members of this group. http://www-1.ibm.com/support/entdocview.wss?uid=swg21137719 http://www-1.ibm.com/support/docview.wss?uid=isg1pTechnote0303 Sincerely, Christopher Coleman Database Analyst Medication Management Mediware Information Systems, Inc.