On Thu, 9 Jun 2011, Emmanuel Noobadmin wrote: > I'm trying to resolve an I/O problem on a CentOS 5.6 server. The > process basically scans through Maildirs, checking for space usage and > quota. Because there are hundred odd user folders and several 10s of > thousands of small files, this sends the I/O wait % way high. The > server hits a very high load level and stops responding to other > requests until the crawl is done.
If the server is reduced to a crawl, it's possible that you are hitting the dirty_ratio limit due to writes and the server has entered synchronous I/O mode. As others have mentioned, setting noatime could have a significant effect, especially if there are many files and the server doesn't have much memory. You can try increasing dirty_ratio to see if it has an effect, eg: # sysctl vm.dirty_ratio # sysctl -w vm.dirty_ratio=50 Steve _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos