Re: Informix and RAID ...OOPS!
Sorry, the page has been put back. http://www.baydel.com/informix.html apologies. With regards to Informix saying RAID is not good, this comes from testing Informix carried out on another RAID vendors system, discovering that JBOD was better than RAID5 and RAID3. Even the Informix storage specialist I spoke with used this document as his bible, so no wonder that the advice was given. Informix people dont't have the time to test every RAID system so they take a shortcut and use the only information that they have - i.e. the internal Informix paper which says use JBOD. When we pointed out that they had only tested one RAID system they got embarrassed. But...they still use the paper! GB ---------- In article <361BF306.BB32FB1@weideneder.de>, Stefan Weideneder <stefan@weideneder.de> wrote: Glenn Brackenridge wrote: > > Hi, > > I wrote something for my employer Baydel > > http://www.baydel.com/informix.html > > Don't confuse fragmentation and RAID. Fragmentation on different volumes > will work fine, but won't give you the benefits of hardware RAID. > Fragmentation on a RAID split into different volumes may suffer from > contention and waste some of the efforts of Informix. If you pick a RAID > system with good performance, and in our case, if the application likes > cache (plenty of writes, and frequent scans, searches, and hot indexes) then > go ahead with the RAID, it will hide the effect of any contention. > > Informix seem to have originally placed themselves into a corner by > discounting the use of RAID when they didn't actually look at enough RAID > options. I don't think that Informix told you to avoid RAID systems. But in some manuals of specific hardware vendors you can still find the hint, that you shouldn't use RAID 5 for databases. Maybe you contacted a guy who made bad experiences with RAID 5 systems. I think it's better to wonder why the I/O is too slow than to conclude that the reason must be the hardware. Don't stop asking until you really know the reason and never ever believe anyone, with the exception of god. Bye Stefan Weideneder