Description of problem:
If the above is not the default, windows guest will drift.
Run windows guest (especially with winXP multimedia playing) and create load on the host and notice time drift.
No drift should be found.
According to Daniel we should have this:
<timer name="rtc" tickpolicy="catchup">
It's fine to do it for all guests.
Old rhel5 hypervisor info (which is still valid w/ interface changes):
Again I have to ask, if it's fine to do it for all guests, why isn't this the default at the qemu level?
Specifically what OS need this to behave properly? Just WinXP? All windows (even win7)?
(In reply to comment #3)
> Again I have to ask, if it's fine to do it for all guests, why isn't this the
> default at the qemu level?
It shouldn't be set for all the guests but for most, nothing bad will happen if it exists (apart from rhel3). That's why we don't do it blindly w/ qemu (in addition to ignorant upstream qemu community w.r.t non x86)
> Specifically what OS need this to behave properly? Just WinXP? All windows
> (even win7)?
All windows flavors
Created attachment 528826 [details]
Use clock timer mode 'catchup' for windows guests
Not a proper fix for upstream inclusion since that requires a bit more code than is worth backporting, but this should solve our issues for RHEL6.
Fixed in python-virtinst-0.600.0-5.el6
Reproduced with the following package:
1. Download a window2008 image from http://fileshare.englab.nay.redhat.com/pub/section3/libvirtmanual/Windows_KVM_images/win2008r2-64.qcow2
3. Create a new guest w08 use the above image with the following steps:
Create a new guest-> name is w08;import existing disk image -> select the downloaded win2008 image; os is windows; versions is microsoft windows server 2008;->
Leave other configure default.
4. Run the guest, log into the guest ,found time is almost same with host.
5. use command #iozone -a to create load on host, and found guest's time is also almost same with host.
6. #virsh dumpxml w08
<timer name='rtc' tickpolicy='catchup'/>
7. # ps -aef | grep qemu
qemu 22784 1 7 18:05 ? 00:01:38 /usr/libexec/qemu-kvm -S -M rhel6.2.0 -enable-kvm -m 1024 -smp 1,sockets=1,cores=1,threads=1 -name xp -uuid ffafeb4c-df29-01c5-1e7e-78f58dbc2759 -nodefconfig -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/xp.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime,driftfix=slew -no-shutdown -drive file=/var/lib/libvirt/images/xp.img,if=none,id=drive-ide0-0-0,format=raw,cache=none -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -netdev tap,fd=23,id=hostnet0 -device rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:3c:b2:ef,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -usb -device usb-tablet,id=input0 -vnc 127.0.0.1:0 -vga std -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4
8. Check other windows guest; such as xp, win03, win7. All of them are OK
So move the status of this bug to 'verified'.
Technical note added. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.
virt-install was not specifying any clock policy for windows guests.
windows guest time would skew from host time
virt-install specifies the tickpolicy 'catchup' for windows guests.
windows guest time is less likely to skew
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
*** Bug 767188 has been marked as a duplicate of this bug. ***