Friday 2 May 2008

Hyper-V on Server Core - Some initial observations and hardware planning

We have had a chance to have some production Windows XP and Vista virtual machines running in Hyper-V on Server Core Standard for a few days now.

We decided to copy over our production VMs to Hyper-V, because that was the only way we were going to get any real experience with the product.

All in all, the experience has been positive.

Some of the high points:
  • VM performance is faster than Virtual Server 2005 R2 SP1 on W2K3 R2 Standard SP2.
    • Single core to single core on an identically equipped 1U Intel Xeon 3000 Series.
    • From VM boot times, to program start up, to running some pretty intense reports in QuickBooks, things move a lot quicker.
  • Adding a second core to the Hyper-V based VM increases performance significantly.
  • Server Core's overhead is a paltry 256MB of RAM, in this case leaving 7.75GB to the VMs.
  • Server Core's hard drive footprint is relatively small, and can be made smaller by removing not needed packages (Server Core blog how-to).
One of the first things we needed to do to get Hyper-V to work with the newer Intel S3000AH series NIC setup in our 1U was to download the Hyper-V RC0 and install it.

We downloaded the MSU file to a company folder share the Server Core system was connected to, copied it over to a local folder on the Server Core machine, then ran the update from the command line from that folder by typing it's full name and hitting Enter.

The RC0 install routine fired up with no issues, rebooted the machine, then ran some more install routines on login.

We needed to have Windows Vista SP1 on the workstation we were going to install the Hyper-V management console (x64 Console, x86 Console) on.

We have run into a few Hyper-V hiccups and a strange VM performance issue:
  • Our Windows Vista SP1 VM that came from a Virtual Server 2005 R2 SP1 with Virtual Machine additions removed would not setup on Hyper-V at all.
    • This is a known limitation at this point
  • Our Hyper-V based server must have read/write permissions given to shared folder where any ISOs reside
    • Access to the ISOs on our Windows based storage server works fine
    • Access to ISOs on an Intel SS4000E in either Local Authentication or Active Directory Authentication Mode will not work.
  • The XP VMs go into some sort of near death pause for anywhere from 15-30 seconds periodically and somewhat randomly.
What we are also finding out with the current setup is that the performance bottleneck has moved from the Windows OS to the storage subsystem. We have discovered that we need a really good hardware accelerated RAID controller to reduce or eliminate that bottleneck.

All in all, as Hyper-V goes through its final development phase into RTM, things can only get better.

Working with both Server Core and Hyper-V has been a really good experience so far. A neat part of the whole endeavour is discovering all of the quick and simple ways one can manage the server from the command line. And subsequently, manage the Full Server 2008 Install in the same manner.

Next up ... PowerShell! ;)

Philip Elder
Microsoft Small Business Specialists

*All Mac on SBS posts are posted on our in-house iMac via the Safari Web browser.


Anonymous said...

any resolution on the random pause issue? The same thing is happenening to me (same setup as you - core, hvrc0, etc...) and it is infuriating

Philip Elder Cluster MVP said...


At this point, no.

The next RC will hopefully address the issue.

From the bit of research done so far though, it looks as to be a problem in the networking stack.