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Diffstat (limited to 'results/classifier/deepseek-2-tmp/output/KVM/1297218')
| -rw-r--r-- | results/classifier/deepseek-2-tmp/output/KVM/1297218 | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/results/classifier/deepseek-2-tmp/output/KVM/1297218 b/results/classifier/deepseek-2-tmp/output/KVM/1297218 new file mode 100644 index 000000000..41b7599cf --- /dev/null +++ b/results/classifier/deepseek-2-tmp/output/KVM/1297218 @@ -0,0 +1,21 @@ + +guest hangs after live migration due to tsc jump + +We have two identical Ubuntu servers running libvirt/kvm/qemu, sharing a Gluster filesystem. Guests can be live migrated between them. However, live migration often leads to the guest being stuck at 100% for a while. In that case, the dmesg output for such a guest will show (once it recovers): Clocksource tsc unstable (delta = 662463064082 ns). In this particular example, a guest was migrated and only after 11 minutes (662 seconds) did it become responsive again. + +It seems that newly booted guests doe not suffer from this problem, these can be migrated back and forth at will. After a day or so, the problem becomes apparent. It also seems that migrating from server A to server B causes much more problems than going from B back to A. If necessary, I can do more measurements to qualify these observations. + +The VM servers run Ubuntu 13.04 with these packages: +Kernel: 3.8.0-35-generic x86_64 +Libvirt: 1.0.2 +Qemu: 1.4.0 +Gluster-fs: 3.4.2 (libvirt access the images via the filesystem, not using libgfapi yet as the Ubuntu libvirt is not linked against libgfapi). +The interconnect between both machines (both for migration and gluster) is 10GbE. +Both servers are synced to NTP and well within 1ms form one another. + +Guests are either Ubuntu 13.04 or 13.10. + +On the guests, the current_clocksource is kvm-clock. +The XML definition of the guests only contains: <clock offset='utc'/> + +Now as far as I've read in the documentation of kvm-clock, it specifically supports live migrations, so I'm a bit surprised at these problems. There isn't all that much information to find on these issue, although I have found postings by others that seem to have run into the same issues, but without a solution. \ No newline at end of file |