[pve-devel] [PATCH qemu-server] fix Bug #615 Windows guests suddenly hangs after couple times of migration

[Wolfgang Link]

Windows has a clock/tick problem when it is live-migrated.
This problem ends in a pseudo freeze status.
The solution is to stop the clock, when we suspend the VM for live-migration.

see man kvm -rtc clock=vm

The drawback is the VM will lose a little time on every live migration.
So with this setting it is recommended to have a time-sync client in the VM to keep the time.
---
 PVE/QemuServer.pm | 1 +
 1 file changed, 1 insertion(+)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index dbd85a0..d3eeac5 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -3002,6 +3002,7 @@ sub config_to_command {
 	    $ostype eq 'wvista') {
 	    push @$globalFlags, 'kvm-pit.lost_tick_policy=discard';
 	    push @$cmd, '-no-hpet';
+	    push @$rtcFlags, 'clock=vm';
 	    if (qemu_machine_feature_enabled ($machine_type, $kvmver, 2, 3)) {
 		push @$cpuFlags , 'hv_spinlocks=0x1fff' if !$nokvm;
 		push @$cpuFlags , 'hv_vapic' if !$nokvm;
-- 
2.1.4