G'day James, On Thu, Apr 25, 2013 at 07:39:27AM +0000, James Harper wrote: > I'm doing some testing and wanted to see the effect of increasing journal > speed, and the fastest way to do this seemed to be to put it on a ramdisk > where latency should drop to near zero and I can see what other > inefficiencies exist. > > I created a tmpfs of sufficient size, copied journal on to that, and started > the OSD. It core dumped pretty quickly which I assume is related to direct io > not being supported. I turned off journal dio and the osd started okay but > never recovered. > > How should I do this? Is there another type of ramdisk I should use or other > journal options I should specify?
It might be because of the copy. Rather than copying, you might try moving it with 'ceph-osd --flush-journal', 'ceph-osd --mkjournal', along the lines of: http://wiki.skytech.dk/index.php/Ceph_-_howto,_rbd,_lvm,_cluster#Add.2Fmove_journal_in_running_cluster Cheers, Chris _______________________________________________ ceph-users mailing list [email protected] http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
