2015-05-28 10:10 GMT+03:00 Richard W.M. Jones <rjones@redhat.com>:
2015-05-27 15:21 GMT+03:00 Richard W.M. Jones <rjones@redhat.com>:
On Wed, May 27, 2015 at 09:38:38AM +0300, NoxDaFox wrote:
* RuntimeError: file receive cancelled by daemon - On r = libguestfsmod.checksums_out (self._o, csumtype, directory, sumsfile) * RuntimeError: hivex_close: do_hivex_close: you must call 'hivex-open' first to initialize the hivex handle - On r =
On Thu, May 28, 2015 at 09:48:41AM +0300, NoxDaFox wrote: libguestfsmod.inspect_os
(self._o)
This error is likely to be -EIO (it's actually a bug in libguestfs that it doesn't report these properly in the error message). However we cannot be sure unless you enable debugging and get the complete messages.
http://libguestfs.org/guestfs-faq.1.html#debugging-libguestfs
Rich.
I'm starting to wonder whether these errors are due to the fact that I compare snapshots of unconsistent disks. If so, is there a way to instruct guestfs to ignore corrupted files?
Are the snapshots "consistent"? - ie. taken in such as way that they provide a single point-in-time view across the whole disk? You mentioned using 'qemu-img convert' before. 'qemu-img convert' on its own will not take a consistent snapshot (well, not unless you pause the guest during the copy, or you use some fancy new backup features recently added to qemu).
It's a bit challenging to generate such logs as the error appears every now ant then. Here's the log related to a "RuntimeError: file receive cancelled by daemon". [...] mount -o /dev/sda2 /sysroot/ The disk contains an unclean file system (0, 0). The file system wasn't safely closed on Windows. Fixing. libguestfs: trace: mount = 0 libguestfs: trace: checksums_out "sha1" "/" "/tmp/tmpAWHkYv" guestfsd: main_loop: proc 1 (mount) took 2.02 seconds guestfsd: main_loop: new request, len 0x38 cd /sysroot/ && find -type f -print0 | xargs -0 sha1sum [ 25.580340] perf interrupt took too long (2540 > 2500), lowering kernel.perf_event_max_sample_rate to 50000 sha1sum: ./Windows/Prefetch/ReadyBoot/Trace7.fx: Value too large for defined data type [ 67.835952] perf interrupt took too long (5048 > 5000), lowering kernel.perf_event_max_sample_rate to 25000 [ 143.304037] perf interrupt took too long (10010 > 10000), lowering kernel.perf_event_max_sample_rate to 12500 pclose: /: Success guestfsd: main_loop: proc 244 (checksums_out) took 245.25 seconds libguestfs: trace: checksums_out = -1 (error) [...] File "/usr/lib/python2.7/dist-packages/guestfs.py", line 1427, in checksums_out r = libguestfsmod.checksums_out (self._o, csumtype, directory, sumsfile) RuntimeError: file receive cancelled by daemon
The error is confusing, but I think you are correct that it happens because the filesystem is unclean at the point at which it was snapshotted, maybe combined with partially written metadata which to the ntfs-3g driver looks like disk corruption.
This is just what happens when you make inconsistent snapshots of disk unfortunately.
My best suggestion would be:
- Catch the exception in Python
- When you hit this error, skip this snapshot and go on to the next one
That may involve rearchitecting your application a bit, but if the error is rare, it seems like the best way to handle it.
An alternative, if you're not doing it already, would be to take a consistent snapshot. Assuming the guest is well-behaved and the filesystem uses journalling and the journalling is implemented correctly, a consistent snapshot should not have such errors.
Rich.
To create the snapshots I'm using the libvirt command snapshotCreateXML with no flag set. Does libvirt support consistent snapshotting or shall I rely on QEMU backup new feature only?