Hello, On Fri, 17 Jun 2016 14:51:08 +0200 Gandalf Corvotempesta wrote: > 2016-06-17 10:03 GMT+02:00 Christian Balzer <chibi@xxxxxxx>: > > I'm unfamilar with Xen and Xenserver (the later doesn't support RBD, > > btw), but if you can see all the combined activity of your VMs on your > > HW in the dom0 like with KVM/qemu, a simple "iostat" or "iostat -x" > > will give you the average IOPS of a device. > > Same of course within a VM. > > I'm able to see the combined activity directly from Dom0. > Good. > With "iostat" should I look for 'tps' column ? > Yes, though you want to look at "iostat -x" to get a breakdown between reads and writes. What's the output from a single run (averages since boot)? > > However that's the average, you're likely to have peaks much higher > > than that. > > For this you'll either have to collect and graph that data > > (collectd/graphite, etc) and/or run something like atop during peak > > hours and watch it or have it write logs with a high sample rate. > > As in, atop can keep a log of all states, but the default interval of > > 10 minutes with Debian is likely too course to spot real peaks. > > See the atop documentation. > > Running "iostat" every seconds, i can see about 800-1000 tps > (transactions per seconds) That sounds extremely high, is that more or less consistent? How many VMs is that for? What are you looking at, as in are those individual disks/SSDs, a raid (what kind)? > I can try to install "atop" but i'm totally new to this, I don't know > how use. Any hint? For starters, run atop in a large window, you will see a lot of details and field names are both pretty obvious and explained in the documentation. > Currently i'm reading the "atop" man page but i don't want to run in > for the whole weekend > with wrong parameters. > Weekend would be the wrong time to look for peaks anyway, wouldn't it? With Debian there's a /etc/default/atop config file, you would want to change the INTERVAL from 600 to at least 60 or even less and then run it for a few hours during peak times. Christian -- Christian Balzer Network/Systems Engineer chibi@xxxxxxx Global OnLine Japan/Rakuten Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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