One of the most controversial blog articles I wrote over the last couple of months definitely was the “Hyper-V crashes youtube movie“  post. The amount of response I had on this post and the follow-up “Will you fight or will you run” was amazing. Of course people where divided in two “camps”, either you liked the post or thought it was FUD. Of course Microsoft responded(1, 2) immediately requesting details and accusing VMware of spreading FUD. Like I said in my follow up article, you guys should have seen this coming and might have been better off just leaving it as it is…

Bruce Herndon has just posted the details of the video, “Setting the Record Straight on the Hyper-V Video“. Now I had a lot of comments from people claiming all sorts of wild stuff, this article sets most of these statements straight.

The following bullet points summarize the quoted bits below:

• The bios was up to date
• Supported and standard hardware
• Hardware fully functional during similar or heavier workloads on ESX
• IDE performance is seriously lacking, although Jeff claims differently in his article.
• Under “heavy load” Hyper-V has serious stability issues (VMs crash, Parent parition BSOD, Hyper-v BSOD)
• Hyper-V has scaling issues
• It seems that Hyper-V isn’t performing well compared to ESX (can I get a full VMmark report please?!?)
  100% at 10 tiles(60VM’s) for Hyper-V vs 14 tiles(84 VM’s) for ESX 3.5. It seems like ESX beats Hyper-V by 40%.
• Linux support is still at a bare minimum

1. There were a number of requests for more details on the system shown in the video. Below is a basic summary of the hardware used:
   Dell PowerEdge R905 with 4 x 2.6GHz Quad Core AMD Opteron 8382
   Firmware version 3.0.2 (latest available)
   128GB DDR2 Memory
   2 x Intel E1000 dual-port NIC
   2 x Qlogic 2462 dual-port 4Gb
   2 x EMC CX3-80 Storage Arrays.

   I want to point out that this particular testbed has performed flawlessly under much heavier loads and VM consolidation ratios during an array of testing running similar workloads on ESX. I am confident that the hardware is fully functional. The hypervisor was the fully-patched RTM version of Hyper-V.

2. The crashes shown in the video occurred when running a total of 11 tiles (66 VMs). We saw the full spectrum of crashes: random subsets of VMs would crash, or more disturbingly the parent partition would BSOD, or most disturbingly the hypervisor itself would BSOD. In this blog posting, Jeff Woolsey of Microsoft dredges up the familiar complaints about VMware’s ESX Benchmark EULA. I have to point out the obvious here – there were no benchmark results in the video. It is quite difficult to gather data when the system reliably crashes during the test. However, I am happy to provide more data to help improve the signal-to-noise ratio in this discussion. I also believe that more data will put the crashes shown on the video into the proper context.The figure below shows throughput scaling relative to the throughput of a single tile. I won’t comment too much other than to say that in my experience with this type of workload, the scaling exhibited by Hyper-V is lower than expected. The drop in throughput for the tenth tile was also surprising.The system crashes shown in Scott’s video occurred when we attempted to run an eleventh tile on the system. System stability under these conditions is the hallmark of true enterprise-class software. While things like poor response time are to be expected in this regime, catastrophic failure is never acceptable, including in the event of a sudden unexpected spike in usage.
3. “If you want to run a virtual machine with a single virtual disk just do it. My best guess is this: Hyper-V only boots from virtual IDE, not virtual SCSI, and whoever ran this test thinks that the test must be run from virtual SCSI for the best performance.”I think most folks would be interested to know that the in the course of our extensive research we tested just such a scenario. In this case the system was a Dell 2950 with dual Intel Xeon X5460 (3.16 GHz) and 32GB of RAM. As you can see below, IDE-only exhibited higher utilization (except at saturation as expected) and lower throughput at every data point. Based on these and other results, we standardized on the IDE/SCSI dual-disk solution to give Hyper-V every possible advantage.

I will probably receive a whole bunch of comments on credibility, objectivity and more… before you do comment read my “Will you fight or will you run” article….