[CentOS-virt] Problem with CentOS 5.3 Xen and Windows Server 2008 HVM DomU

Ben M. centos at rivint.com
Mon Oct 19 16:14:26 UTC 2009

I had that issue when I first installed. The clock still acts up once in 
a while if I take the system down entirely for a few hours, which won't 
happen now that it is in the rack.

This seems to work for me at the moment, with or without Xen GPLPV, 
though GPLPV "safens" your install (Registry Hive errors without it). 
YMMV and I am not shaken out yet!

- Xen with UTC off. NTP Service getting time. "Stock CentOS 5.3 repos"
- Win2K8 x32 (Web Edition) (plus SQL Express 2005), NTP off (aka 
Synchronize with Internet Time server).

If using Xen GPLPV drivers there are some other things I changed, these 
may be strictly hardware platform relative (I'm on AMD x86_64, MCP55 
chipset type, nvidia Fake Raid1 - two sets, dmraid not md).

Windows Device Manager:
- Xen Disk Drivers: Optimize for quick removal. Pretty sure this disable 
write caching.
- Xen Net Device Drivers: Checksum Offload (Disabled), Large Send 
Offload (Disabled)

- I do not have DVD/CD access working as Hardware or as virtualized iso 
yet. I do not have any USB devices showing (have an UPS monitored via 
USB in Xen kernel). I don't need any of these at the moment in Win2k8.

- I haven't tried a Win2K3 installation yet. So far I am very 
disappointed with Win2K8 and I'm calling Windows Vista Server here. 
20gigs of partition space needed (excluding sql express) to just serve 
the first, static, web page? Gimme a break!

SQL Express 2008 was a resource cpu-churning pig and sluggish, 
downgraded to SQL Express 2005 (with some fussing) for now, seems okay 
so far. Not fully tested. The whole 2008 web package is like using an 
elephant to shuck a peanut for you.

- There is a way to reduce the memory Windows 2008 takes at startup. I 
cannot find this interface click path at the moment (again). But start 
it at 2gig, work your way up. If you have shadow memory declared in the 
xend conf for it seem to ADD that to the total memory Win2k8 uses and I 
got flakey at the 4G border especially with the shadow declared in the 
xend conf file. 2G ram with SQL 2005 Express loaded local has been more 
than enough to handle a moderately high amount of webserving once its 
tweaked out. Reducing the memory in the xend conf did NOT seem to stop 
Win2k8 from taking as much as it could as a pure hvm or with the Xen 
GPLPV drivers.

Considerations about memory:


Veli-Pekka Kestilä wrote:
> Hi,
> I have CentOS 5.3 64bit and couple of Windows Server 2008 32Bit DomU's 
> on it.
> Problem is that I got hit with the "A clock interrupt was not recevied 
> on a secondary processor within the allocated time interval" Blue Screen 
> when trying to run with more than one CPU
> When searching around I found that official XEN distribution 
> (development version) has some fixes for it, but is there anything I 
> could do on CentOS / windows quest to get the things working with more 
> than one CPU.
> Greetings,
> Veli-Pekka Kestilä
> _______________________________________________
> CentOS-virt mailing list
> CentOS-virt at centos.org
> http://lists.centos.org/mailman/listinfo/centos-virt

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