On Thu, Jun 30, 2011 at 4:38 AM, Alexander Dalloz ad+lists@uni-x.orgwrote:
Am 30.06.2011 08:36, schrieb Steve Barnes:
Although it would really be interesting to me to see scheduler settings
that would indeed allow something of a 'privileged' ssh or an OOB console that would be responsive even under a punishing load with lots of swapping, which is what the OP originally asked about.
I'd be interested to hear thoughts on this. We have a small 1U test
server with 2 entry-level SATA drives that was brought to its knees twice this week by an overzealous Java process. Load averages were up around 60+ and as a result, SSH access would timeout. I don't know if this behaviour is typical across operating systems, but it's frustrating to find yourself locked out a server just because a single process went to town on the i/o subsystem.
Cheers
Steve
CentOS 6 will support cgroups, by which you can control cpu, memory and I/O.
http://www.mjmwired.net/kernel/Documentation/cgroups.txt
http://www.mjmwired.net/kernel/Documentation/cgroups/blkio-controller.txt
Just tried the disktop.stp script on a Linux 2.6.38 and it looks nice. The possibilities! :)
http://sourceware.org/systemtap/examples/io/disktop.stp