RE: HP vs Informix mirroring

Funny, but we had exactly the same set up: RAID-5, HP/UX 10.20 and Informix 7.23UC1, but performance decreased when we went to a (Informix) software mirroring scheme (Raid 1/0? - I can never remember). I'm fairly convinced this was because it has a capacious and expensive 3rd party disk controller and cache. My gut feeling would be to avoid RAID - 5 like the plague - mainly due to the inability to use table fragmentation. One interesting thing that came up on this particular machine is that in 7.23+, on an HP/UX 10.20 box, with an ANSI database, performance dies, by a factor of many THOUSANDS, when you have more than about 4 million records in the database. Apparently, Informix loses all grip of query paths, and starts doing sequential scans all over the place. Also, with post 7.23x ANSI databases, dbschema crashes the engine when run. AND (will this list never end?)there is a bug in HP/UX 10.20 that crashes (i.e. reboots) the whole box after a few minutes of usage in 7.23.uc4+. Ahhhh Informix. Kevin Crisp -----Original Message----- From: Ray Garrison [mailto:apsnet@ix.netcom.com] Sent: Wednesday, March 18, 1998 2:18 PM To: informix-list@iiug.org Subject: Re: HP vs Informix mirroring In article <350EEDF9.187C@po1.cobe.com>, Ed Bidinotto <eb06709@po1.cobe.com> wrote: >We are running HP-UX 10.20 with Informix 7.23UC1 and are looking at >either working with Raid 5 or going with scsi mirroring. We have seen >great performance with raid 0+1 on another server and have not had great >results with raid 5 so here's my question to the masses. > >Does anyone have any stats on performance or even recommendations as to >which one of the above is better? I've always heard that if you are >going to be mirroring - then go with Informix however I think that >person just said that because they didn't know anything about HPUX >mirroring. I don't know the pros and cons, hopefully someone does. > >All ideas, recommendations, suggestions are welcome. > >Tks in advance >Ed > >edbid @ cobe.com Do not use Raid 5. I had a HP model 20 array maxed out with cache, with dual controllers, yada yada yada, and performace was so poor many programs simply never finished. On a D370 system, dual PA7200 processor, 512 Meg RAM with 40 rather slow SCSI single ended drives, I had a billing query than completed in about 4 hours. Substituting the array for the drives, no matter how we configured the damn thing, the query never completed (never meaning not in 3 days, anyway.) Ray Garrison