Powervault 650F slow performance
Posted on 2004-03-24
Here's my situation: I have a Dell powervault 650F fibre channel array attached to a poweredge 2400 via 1 Qlogic QL2200/66 HBA using HSSDC - DB9 cabling. The PV is configured with 1 5-disk RAID 5 LUN right now and I am basically in the testing phase. The problem I have is in slow performance with the PV; copying a 200 MB file to the RAID 5 array takes about 10 seconds, which I consider decent. The real problem is in reading the file, if I copy that same file from the RAID 5 array to the local disk on the server it takes around 90 seconds. I have tried it with read caching for the LUN enabled and disabled, with the same outcome. I have also tried several different types of RAID LUNs to see if it could have been a RAID 5 issue, which it doesn't appear to be as RAID 1 had the same performance (besides which EMC claims that RAID 5 should be the fastest on a PV, aka Clariion 5600). The drives in the PV are 18 GB 10K RPM Cheetah, and I assume I should be getting far greater transfer rates than 2 MB/s from a 10K RPM fibre channel drive. If I can't get this thing to read at a decent speed it is basically garbage, so if anyone has any ideas on what could be causing such poor performance here's your chance to shine.