[Bug 511620] Re: write errors on virtual disc during install

[Dave Gilbert]

Hi Dustin,
  Apologies for the delay (I mostly do stuff at the weekend).

I've just tried current Lucid with qemu-kvm 0.12.3-0ubuntu7and kernel 2.6.32-15-generic #22-Ubuntu and the 
lucid-alpha3 desktop amd64 iso for the guest, and the problem is the same.

The backing disk is a raw lvm2 logical volume (/dev/mapper/main-fiddle2disk), it's in a normal volume group with
a single physical volume of /dev/sda3 which is a partition on the SATA disk.

The failure seems to be 100% repeatable - the block number it fails at
is non-repeatable - I have tried this about 5 times now (once with this
latest version, a few more times with previous versions) and have not
had a successful installation.  I have managed an installation using an
emulate SCSI disk rather than virtio.

One thing I saw today which I don't believe I had previously seen is in
the host dmesg I'm seeing some audit entries:

[10772.370241] type=1503 audit(1267889473.222:28):  operation="capable" pid=5766 parent=1 profile="libvirt-fd06659e-3354-cb8e-71d9-cfeeff86e60f" name="sys_ptrace"
[10772.370528] type=1503 audit(1267889473.222:29):  operation="capable" pid=5789 parent=1 profile="libvirt-fd06659e-3354-cb8e-71d9-cfeeff86e60f" name="sys_ptrace"
[10772.379636] type=1503 audit(1267889473.232:30):  operation="capable" pid=5792 parent=1 profile="libvirt-fd06659e-3354-cb8e-71d9-cfeeff86e60f" name="sys_ptrace"
[10788.216465] type=1503 audit(1267889489.092:31):  operation="capable" pid=5767 parent=1 profile="libvirt-fd06659e-3354-cb8e-71d9-cfeeff86e60f" name="sys_rawio"
[10788.247112] type=1503 audit(1267889489.122:32):  operation="capable" pid=5766 parent=1 profile="libvirt-fd06659e-3354-cb8e-71d9-cfeeff86e60f" name="sys_rawio"
[10791.174155] type=1503 audit(1267889492.052:33):  operation="capable" pid=5766 parent=1 profile="libvirt-fd06659e-3354-cb8e-71d9-cfeeff86e60f" name="sys_rawio"
[10791.429616] type=1503 audit(1267889492.312:34):  operation="capable" pid=5767 parent=1 profile="libvirt-fd06659e-3354-cb8e-71d9-cfeeff86e60f" name="sys_rawio"
[10820.832664] type=1503 audit(1267889521.762:35):  operation="capable" pid=5766 parent=1 profile="libvirt-fd06659e-3354-cb8e-71d9-cfeeff86e60f" name="sys_rawio"

but it's not clear to me that's related and you would have thought it
would have failed earlier if it couldn't do any IO??

Todays failure happened about 5% through the install and the errors in
the guest's dmesg were:

end_request: I/O error, dev vda, sector 25702959
Buffer I/O error on device vda1, logical block 3212862

SMART on the host disk still looks good ('No Errors logged').

Dave

-- 
write errors on virtual disc during install
https://bugs.launchpad.net/bugs/511620
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