On Sun, 04 Oct 2009, Anthony Tibbs wrote: > number of years now. All was well until last night when performance > went down the tubes and I started seeing high I/O wait times. I'm > pretty sure this is a problem on the hosting end, but in trying to > diagnose the source of the I/O congestion, the closest I could come Rebuilding RAID arrays? "sharing" the spindles with some other virtual server whose workload seeks the disk around like crazy? > to answer was that ctl_cyrusdb is reading/writing about 15-20 4096b > blocks (from the /var/imap/db/* files) per second. This amounts > to read/write throughput in the 250kb/second range. Even a laptop HD can do > 200 blocks/s. If you're *sure* it is not the storage/disk going bonkers, or your provider giving you the shaft on the sharing of IOPS to the real storage for your virtual server, it means that box (all virtual servers AND the hypervisor) needs a switft boot to the head because the IO scheduler went insane. -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
