On Sun, 30 Nov 2003, Dustin Puryear wrote: > I am studying a SCO OSR5 system that has serious performance issues. I am > interested in hearing your critiques, suggestions, and corrections about my > performance analysis, suggested courses of action, and, in general, anything > else that you feel is relevant. I also hope that this post and resulting > thread will help others in troubleshooting performance issues on a SCO or > Unix server, since it can be something of a mystic art.
Dustin, Pretty detailed analysis, i'd say you hit the nail on the head with the I/O bottleneck. I'll just throw in my comments on Unix performance tuning (mostly AIX and Linux). In my experience, these are the bottlenecks you look for, in this order: Application Memory I/O CPU Network The order is very important. For instance, a memory problem could manifest itself as an I/O problem (swapping), Buying more disks/controllers would let you swap faster (haha), but wouldn't help the main memory problem. Memory and I/O could also cause high CPU (load avg's), and all of those could affect network performance. Looks like you definitely have a i/o bottleneck. But before buying more hardware, i would look at the application. Can you tell which queries are being run at peak times? Are all your database indexes ok? Maybe you're missing an index. Check with the vendor and see if any recent service packs address performance issues, see if the queries are efficient, see if they have any DB tuning guidelines, see if you can tune any db parameters yourself. Balance all of that with your cost vs. time. If you're looking at a $50k disk subsystem, then yea you have to do all that stuff. But a few hundred dollars for a new disk, it's probably not worth your time. If this is production data that they NEED, i would install a second disk and RAID-1 everything just for the data protection. If the disk fails, it may be hours (perhaps days) to restore everything, and that's only if they're religious with tape backups. Ideally, you'd have two SCSI controllers, with 2 disks on each controller. One set RAID-1 for the OS, one set RAID-1 for the app/DB. Realistically ($$$), i'd at least get one more disk to mirror the first. It should help the performance also, esp if you put in on a different controller (maybe on a different PCI bus!). ray -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Ray DeJean http://www.r-a-y.org Systems Engineer Southeastern Louisiana University IBM Certified Specialist AIX Administration, AIX Support =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
