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. Regards, Aurelien -- .''`. Aurelien Jarno | GPG: 1024D/F1BCDB73 : :' : Debian developer | Electrical Engineer `. `' [EMAIL PROTECTED] | [EMAIL PROTECTED] `- people.debian.org/~aurel32 | www.aurel32.net ------------------------------------------------------------------------- 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
