Re: To STRIPE, or not To STIPE, That is the question

krwall@uswest.net wrote: > > Graham mitchell <grammi007@classic.msn.com> wrote: > > Hi all, > > > Does anybody KNOW. Really KNOW if stripping does > > improve performance on AIX if you use LVM > > stripping > > > I am about to do a gargantium data reorg onto > > 76Gb of new disk space, and do not have the time or > > resources to experiment. > > > Have you been here before ?! > > There are too many variables in the mix to say for certain. > I, for one, wouldn't do it without testing and lotsa backup, > especially in a production environment. > > If your running RAID on an SP/2, for example, with 20 uniprocessor > nodes, 19/20 of your I/O is going to be remote, which introduces > all sorts of overhead. If, on the other hand, you have 4 > 5-processor nodes, way more of your I/O is local, so you might > see significant performance gains using RAID. It *simply* has > to be tested. I'll go out on a limb and say, as I always do: 1) Yes striping improves performance tremendously. 2) AVOID RAID 5 LIKE THE PLAGUE use RAID 3 if costs are a concern or RAID 1+0 for maximum performance and safety! RAID 5 JUST DOES NOT WORK! Write performance stinks, protection from media errors is non-existant, and recovery even from a drive failure (the only actual situation RAID5 protects against) ties up 90%+ or your I/O bandwidth during the entire recovery! DO NOT USE RAID 5 PERIOD end of discussion. Art S. Kagel