On 03/29/2013 09:46 PM, Josh Durgin wrote: > The issue was that the qemu rbd driver was blocking the main qemu > thread when flush was called, since it was using a synchronous flush. > Fixing this involves patches to librbd to add an asynchronous flush, > and a patch to qemu to use it. > > The ceph patches are in the next and master branches, and will be > backported to bobtail. The patch for qemu is at [1] if anyone wants to > try it out. > > Josh > > [1] http://lists.gnu.org/archive/html/qemu-devel/2013-03/msg05367.html Hi, I can confirm that it performs VERY well now under load, no more I/O hangs. Important for me was to set the VM-Type to pc-1.3 in libvirt, like this: <type arch='x86_64' machine='pc-1.3'>hvm</type>. with my pc-1.0 setting before it was VERY slow (not ceph, but the virtual system, this was a qemu-issue). The patch you posted to the qemu-mailinglist has not been included into their master branch yet as far as I've seen. Are they reliable in integrating it into upstream? This patch is REALLY relevant, IMHO, we should urge them to integrate it sooner than later. Wolfgang -- DI (FH) Wolfgang Hennerbichler Software Development Unit Advanced Computing Technologies RISC Software GmbH A company of the Johannes Kepler University Linz IT-Center Softwarepark 35 4232 Hagenberg Austria Phone: +43 7236 3343 245 Fax: +43 7236 3343 250 wolfgang.hennerbichler@xxxxxxxxxxxxxxxx http://www.risc-software.at _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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