Robert Haas wrote: > I'm kind of surprised that there are disk I/O subsystems that are so > bad that a single thread doing non-stop I/O can take down the whole > server. Is that normal? No. > Does it happen on non-Windows operating > systems? Yes. My 3ware 8500-8 on a Debian Sarge box was so awful that launching a terminal would go from a 1/4 second operation to a 5 minute operation under heavy write load by one writer. I landed up having to modify the driver to partially mitigate the issue, but a single user on the terminal server performing any sort of heavy writing would still absolutely nuke performance. I landed up having dramatically better results by disabling the controller's RAID features, instead exposing each disk to the OS separately and using Linux's software RAID. > What kind of hardware should I not buy to make sure this > doesn't happen to me? 3ware's older cards. Apparently their new ones are a lot better, but I haven't verified this personally. Anything in RAID-5 without a BBU. Anything at all without a BBU, preferably. -- Craig Ringer -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
