On Thu, Jun 05, 2014 at 12:54:19PM -0400, Tom Horsley wrote: > On Thu, 05 Jun 2014 10:30:31 -0600 > Eric Blake wrote: > > > What caching mode are you requesting? tmpfs can't (yet) support > > O_DIRECT, and if the caching mode you request causes qemu to try > > O_DIRECT, that would explain why it is failing. > > Is that qemu's default mode? I don't think anyone is explicitly > setting it, but I'll have to find out from the folks actually > trying this.
I can't recall what the defaults are, but if you run 'virsh dumpxml' it will tell you the cache mode for each drive. In any case, cache='none' (ie. O_DIRECT) won't work, and you shouldn't use it for throwaway test machines anyway. Since tmpfs always disappears at reboot, any machine you create on a tmpfs is a throwaway one, whether you intended that or not! Use cache='unsafe' on tmpfs. (This advice applies to libguestfs, virt-builder, etc too) For more info on caching modes, see: http://rwmj.wordpress.com/2013/09/02/new-in-libguestfs-allow-cache-mode-to-be-selected/ Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com libguestfs lets you edit virtual machines. Supports shell scripting, bindings from many languages. http://libguestfs.org _______________________________________________ virt mailing list virt@lists.fedoraproject.org https://admin.fedoraproject.org/mailman/listinfo/virt
