Re: Informix OnLine on RAID drives

Neil Truby wrote: > > Melody Fallah-Khair wrote: > > > > Hello, > > > > Has anybody experienced setting up Informix Online 7.x on > > RAID (Redundant Array of Independent Disks) disk drives? Any performace > > improvement or suggestion for how to set them up (RAID 0, 1, 2, ...6)? > > > > I'm wondering specially between using either Informix mirroring or > > hardware mirroring provided by RAID 1. The I/O performance is an > > important factor to us. > > > > Thanks > > Almost every paper I've read by those I respect advocate hardware > mirroring in preference to RDBMS mirroring. At my site, we have > > In my previous site, I used RAID 5 on our database servers (not Informix > though). Again, performance was acceptable, but the drawbacks more At Bloomberg we stripped RAID 5 for most filesystems and began using it for Informix also. It has been nothing but trouble! Admittedly this is partly because for some as yet unknown reason, on our platform (DG/UX w/ DG Clarion RAID), Informix detects the RAID failures, even though the RAID system has replaced the data and returned corrected blocks. Informix also detects an error when the bad drive is replaced. Anyway, we recently bit the bullet and started using mirrored stripe sets on new installations. Performance is MUCH MUCH MUCH better and reliability is way up! We are using hardware mirroring (though I personally prefer Informix mirrors since I have control rather than the System Admins). We mirror a 20 to 30 way stripe set and get >30MB/sec write throughput (I stop testing at 30MB/sec). Informix has a White Paper entitled RAID and Informix Database, by Ken Bendix in ATG which is available from their web site. Their testing recommends hardware mirroring over software mirroring and Informix Mirror (slightly) over OS software mirroring. This is a very conprehensive report, read it. Art S. Kagel kagel@bloomberg.com