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 ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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