Maybe nothing to do with your issue, but I was having problems using librbd with blktap, and ended up adding: [client] ms rwthread stack bytes = 8388608 to my config. This is a workaround, not a fix though (IMHO) as there is nothing to indicate that librbd is running out of stack space, rather that stack is being clobbered and this works around it. I spent a fair bit of time trying to debug it but could never pin it down. James > -----Original Message----- > From: ceph-users-bounces@xxxxxxxxxxxxxx [mailto:ceph-users- > bounces@xxxxxxxxxxxxxx] On Behalf Of John Morris > Sent: Tuesday, 29 October 2013 6:01 AM > To: ceph-users@xxxxxxxxxxxxxx > Subject: Ceph + Xen - RBD io hang > > I'm encountering a problem with RBD-backed Xen. During a VM boot, > pygrub attaches the VM's root VDI to dom0. This hangs with these > messages in the debug log: > > Oct 27 21:19:59 xen27 kernel: > vbd vbd-51728: 16 Device in use; refusing to close > Oct 27 21:19:59 xen27 xenopsd-xenlight: > [xenops] waiting for backend to close > Oct 27 21:19:59 xen27 kernel: > qemu-system-i38[2899]: segfault at 7fac042e4000 ip 00007fac0447b129 > sp 00007fffe7028630 error 4 in qemu-system-i386[7fac042ed000+309000] > > More details here: > > http://pastebin.ca/2472234 > > - Scientific Linux 6 > - 64-bit, Phenom CPU > - Ceph from RPM ceph-0.67.4-0.el6.x86_64 > - XenAPI from Dave Scott's technology preview > - two btrfs-backed OSDs with journals on separate drives > - various kernels, incl. 3.4.6 from Dave Scott's repo and 3.11.6 > from elrepo.org. > > This thread (whose Subject: I borrowed) describes what I'm seeing quite > well, but no resolution was posted: > > http://comments.gmane.org/gmane.comp.file-systems.ceph.user/3636 > > In my case, udevd starts a 'blkid' process that holds /dev/xvdb open. > Like in James's case, any interaction with the device will hang, and > usually can't be killed. This same problem prevents the machine from > completing shutdown. > > In that thread, Sylvain Munaut says the OSD and kernel driver shouldn't > be run in the same host. I believe my setup does not violate that, > since the rbd kernel module is not loaded, and instead the device is > attached through the xen_blkfront module instead. > > Thanks- > > John > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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