Ernie Dunbar
2016-Apr-21 20:10 UTC
[Gluster-users] Performance tuning: How do I measure the performance of IMAP-on-Gluster?
Hi everyone. My Gluster cluster is finally behaving fairly well, CPU, disk and network performance has returned to a stable state, and I'd like to start doing some performance tuning. To do that though, we need to have some metrics to see if the changes we make, are making any difference at all. The basic problem I'm trying to solve is how slow IMAP and Webmail are on our high-availability cluster. All of our e-mail is stored in Maildir format on the Gluster drive, and as a result, using Webmail to "read the next message" is something that takes a couple of seconds, even if we go back to a file that's been read recently and should be cached. I'm not entirely sure how to measure that with the `time` command on the Unix command line in any consistent manner, and other commands (like `ls` or `cat` or `du`) do work a lot faster if repeated within a short period of time. It appears to be the case that producing consistent results (especially the results that matter the most to the customers) basically requires an IMAP connection to read a message. I need some other ideas about how I can perform this test. Your help will be much appreciated.