On Sun, Apr 01, 2012 at 06:52:27PM +0200, Tim Niemueller wrote: > Hi all. > > To test our robot software against the newest and shiniest compilers and > libs we have a rawhide VM. Today I noticed a very annoying problem > (after not using the VM for a while), but I'm not sure if it's on our > side or if I should file a bug. > > The VM is frequently unable to access its root partition (using virtio > for this VM). SSH connection end with "broken pipe", if locally on the > machine trying to execute "dmesg" it only says "cannot find /bin/dmesg". > In the time when the error appears until I loose the connection was once > able to do "cat /proc/kmsg" showing errors on /dev/vda. In the libvirt > log on the host (CentOS 6.2 using libvirtd and virt-manager) I see the > following entries popping up in these situations: > > block I/O error in device 'drive-virtio-disk0': Permission denied (13) > > SELinux' audit.log is quiet. And the VM runs, and sometimes I can work > on it for 30mins straight, sometimes not even for 30secs. Any idea what > might be causing this intermittent problem? > > During investigation I noticed that the very same message appears every > now and then in other VM's logs as well. They are running CentOS 6.2, > and one is FreeBSD 9.0. But in those I do not see the broken connection > or "cannot find file" problems. > > The VM's disks are logical volumes in the same volume group. The machine > is a Dual Xeon Quad-Core with a speedy RAID array hosting the VG. > > Does someone have a similar problem, or can give ideas how to fix or > investigate, and if to file a bug, which component to target? I'm not > even sure if it's a CentOS or a rawhide thing, though I assume the latter... Is the host RAID array using 4K sectors? Look at the files in /sys/block/<device>/queue and compare with: http://libguestfs.org/virt-alignment-scan.1.html#linux_host_block_and_i_o_size Secondly, attach a virtual serial port to the guest and boot it using the kernel command line parameter: console=ttyS0,115200. Then take a look at the boot messages. Thirdly, look at /var/log/libvirt/qemu/*.log Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones libguestfs lets you edit virtual machines. Supports shell scripting, bindings from many languages. http://libguestfs.org -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel
