Aurelien Jarno wrote: > On Sat, Jul 21, 2007 at 12:46:29PM -0500, Anthony Liguori wrote: > >> Aurelien Jarno wrote: >> >>> Hi all, >>> >>> For a long time I am seeing data corruption in guests when using KVM, >>> but I am convinced only since today that the problem comes from KVM. >>> >>> The symptoms are a few bytes that are mangled to 0x00 in a file that has >>> been written. For now I have only seen 2 or 4 consecutive bytes mangled, >>> but that may due to statistics given the limited samples. >>> >>> The problem appears very rarely. I am only seeing it when doing huge >>> compilations (for example gcc or glibc), and not for every build. Note >>> that I am only detecting build failures, so I can miss some corruptions. >>> >>> Note that I have observed the problem on GNU/Linux, GNU/kFreeBSD and >>> plain FreeBSD, for both 32 and 64-bit guests. I always used 64-bit >>> hosts, and I have seen the problem on both Core 2 and Athlon 64 CPU >>> (always multi-core). >>> >>> I have never seen such corruptions using QEMU, so I would say the >>> problem does not comes from the disk emulation, though it may be due to >>> statistics. Note that I have made a lot of compilation in a MIPS QEMU >>> guest (a few hundred of hours), without any problem. This platform uses >>> the same IDE controller as the one in KVM. >>> >>> Does anybody have seen the same kind of problem? Without a way to >>> reproduce the corruption, I think it will be very difficult to debug >>> the problem. >>> >>> >> What sort of disk are you using (qcow2?) >> >> > > I am using raw files for the disk in all cases. > > Note that I have just seen a three bytes corruption. Building the glibc > seems to be a good way to reproduce the bug, as a lot of source files > are generated on the fly during the build, and as GCC does not like > source files with 0x00. > > I will try to do the same compilation using a NFS mount, to see if it > comes or not from the IDE controller emulation. >
Can you do the same build on the host without corruption? Are you sure it's not a bad disk? Regards, Anthony Liguori > Regards, > Aurelien > > ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
