We are using RAID-5 for most of our user home directories: 1. on the way out are plain disks RAIDed using Solstice Disk Suite on our Solaris servers. The reason for not continuing is that the degradation in system performance is particularly steep once a certain threashold is reached, to a point where it becomes difficult to judge whether the problems are due to AFS or the RAID 'subsystem'. Actually, on a SparcStorageArray 214 (which is basically just plain disks as well but with a cache memory) we did not see such a steep degradation - at least as long as the RAID does not reconstruct the parity because of a disk failure. 2. we're extremely pleased with Sun's SparcStorageArray 2000 which is a hardware RAID controller with write-back cache. We run 35 9GB disks in 7 4+1 RAID sets split over two Ultra-2 AFS servers. No problems so far. The RSM2000 is no longer offered I believe but has been replaced by the A<some-thousand> series. 3. we bought IBM SSA disks earlier this year and are about to introduce them into the AFS service. The RAID-5 is implemented on the SSA host attachment card. The disks are 9GB disks and we plan to set them up as 4+1 configurations as in the Solaris case. Our benchmarks show that the RAID is slower than the RSM2000, but still significantly faster than plain disks RAIDed in software. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Rainer Toebbicke http://wwwcn1.cern.ch/~rtb -or- [EMAIL PROTECTED] O__ European Laboratory for Particle Physics(CERN) - Geneva, Switzerland > | Phone: +41 22 767 8985 Fax: +41 22 767 7155 ( )\( )
