On Thu, 17 Jan 2008, Sean Davis wrote:
We have a machine that serves as a fileserver and a database server. Our server hosts a raid array of 40 disk drives, attached to two3-ware cards, one 9640SE-24 and one 9640SE-16. We have noticed that activity on one controller blocks access on the second controller, not only for disk-IO but also the command line tools which become unresponsive for the inactive controller. The controllers are sitting in adjacent PCI-express slots on a machine with dual-dual AMD and 16GB of RAM. Has anyone else noticed issues like this? Throughput for either controller is a pretty respectable 150-200MB/s writing and somewhat faster for reading, but the "blocking" is problematic, as the machine is serving multiple purposes. I know this is off-topic, but I know lots of folks here deal with very large disk arrays; it is hard to get real-world input on machines such as these.
there have been a lot of discussions on the linux-kernel mailing list over the last several months on the topic of IO to one set of drives interfearing with IO to another set of drives. The soon-to-be-released 2.6.24 kernel includes a substantial amount of work in this area that (at least on initial reports) is showing significant improvements.
I haven't had the time to test this out yet, so I can't add personal experiance, but it's definantly something to look at on a test system.
David Lang ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
