Conclusions so Far

Both VMmark and vApus Mark I seem to give results that are almost black and white. They give you two opposite and interesting data points. When you are consolidating extremely high numbers of VMs on one physical server, the Xeon Nehalem annihilates, crushes, and walks over all other CPUs including its own older Xeon brothers… if it is running VMware ESX 4.0 (vSphere). Quickly looking at the VMmark results posted so far seems to suggest you should just rip your old Xeon and Opteron servers out of the rack and start again with the brand-spanking new Nehalem Xeon. I am exaggerating, but the contrast with our own virtualization benchmarking was quite astonishing.

vApus Mark I gives the opposite view: the Xeon Nehalem is without a doubt the fastest platform, but the latest quad-core Opteron is not far behind. If your applications are somewhat similar to the ones we used in vApus mark I, pricing and power consumption may bring the Opteron Shanghai and even the Xeon 54xx back into the picture. However, we are well aware that the current vApus Mark I has its limitations. We have tested on ESX 3.5 Update 4, which is in fact the only available hypervisor from VMware right now. For future decisions, we admit that testing on ESX 4.0 is a lot more relevant, but that does not mean that the numbers above are meaningless. Moving towards a new virtualization platform is not something even experienced IT professionals do quickly. Many scripts might not work properly anymore, the default virtualization hardware is not compatible between the hypervisor, etc. For example, ESX 3.5 servers won't recognize the version 7 hardware from ESX 4 VMs. In a nutshell: if ESX 3.5 is your most important hypervisor platform, both the Xeon 55xx, 54xx, and quad-core Opteron are very viable platforms.

It is also interesting to see the enormous advances CPUs have made in the virtualization area:

  • The latest Xeon 55xx of early 2009 is about 4.2 times faster than the best 3.7GHz dual-core Xeons of early 2006.
  • The latest Opterons are 2.5 times better than the slightly faster clocked 3.0GHz dual-core Opterons of mid 2007, and based on this we calculate that they are about 3 times faster than their three year older brothers.

Moving from the 3-4 year old dual-core servers towards the newest quad-core Opterons/Xeons will improve the total performance of your server by about 3 to 4 times.


What about ESX 4.0? What about the hypervisors of Xen/Citrix and Microsoft? What will happen once we test with 8 or 12 VMs? The tests are running while I am writing this. We'll be back with more. Until then, we look forward to reading your constructive criticism and feedback.

I would like to thank Tijl Deneut for assisting me with the insane amount of testing and retesting; Dieter Vandroemme for the excellent programming work on vApus; and of course Liz Van Dijk and Jarred Walton for helping me with the final editing of this article.

Caches, Memory Bandwidth, or Pure Clock Speed?
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  • Bandoleer - Thursday, May 21, 2009 - link

    I have been running Vmware Virtual Infrastructure for 2 years now. While this article can be useful for someone looking for hardware upgrades or scaling of a virtual system, CPU and memory are hardly the bottlenecks in the real world. I'm sure there are some organizations that want to run 100+ vm's on "one" physical machine with 2 physical processors, but what are they really running????

    The fact is, if you want VM flexability, you need central storage of all your VMDK's that are accessible by all hosts. There is where you find your bottlenecks, in the storage arena. FC or iSCSI, where are those benchmarks? Where's the TOE vs QLogic HBA? Considering 2 years ago, there was no QLogic HBA for blade servers, nor does Vmware support TOE.

    However, it does appear i'll be able to do my own baseline/benching once vSphere ie VI4 materializes to see if its even worth sticking with vmware or making the move to HyperV which already supports Jumbo, TOE iSCSI with 600% increased iSCSI performance on the exact same hardware.
    But it would really be nice to see central storage benchmarks, considering that is the single most expensive investment of a virtual system.

  • duploxxx - Friday, May 22, 2009 - link

    perhaps before you would even consider to move from Vmware to HyperV check first in reality what huge functionality you will loose in stead of some small gains in HyperV.

    ESX 3.5 does support Jumbo, iscsi offload adapters and no idea how you are going to gain 600% if iscsi is only about 15% slower then FC if you have decent network and dedicated iscsi box?????
  • Bandoleer - Friday, May 22, 2009 - link

    "perhaps before you would even consider to move from Vmware to HyperV check first in reality what huge functionality you will loose in stead of some small gains in HyperV. "

    what you are calling functionality here are the same features that will not work in ESX4.0 in order to gain direct hardware access for performance.
  • Bandoleer - Friday, May 22, 2009 - link

    The reality is I lost around 500MBps storage throughput when I moved from Direct Attached Storage. Not because of our new central storage, but because of the limitations of the driver-less Linux iSCSI capability or the lack there of. Yes!! in ESX 3.5 vmware added Jumbo frame support as well as flow control support for iSCSI!! It was GREAT, except for the part that you can't run JUMBO frames + flow control, you have to pick one, flow control or JUMBO.

    I said 2 years ago there was no such thing as iSCSI HBA's for blade servers. And that ESX does not support the TOE feature of Multifunction adapters (because that "functionality" requires a driver).

    Functionality you lose by moving to hyperV? In my case, i call them useless features, which are second to performance and functionality.



  • JohanAnandtech - Friday, May 22, 2009 - link

    I fully agree that in many cases the bottleneck is your shared storage. However, the article's title indicated "Server CPU", so it was clear from the start that this article would discuss CPU performance.

    "move to HyperV which already supports Jumbo, TOE iSCSI with 600% increased iSCSI performance on the exact same hardware. "

    Can you back that up with a link to somewhere? Because the 600% sounds like an MS Advertisement :-).

  • Bandoleer - Friday, May 22, 2009 - link

    My statement is based on my own experience and findings. I can send you my benchmark comparisons if you wish.

    I wasn't ranting at the article, its great for what it is, which is what the title represents. I was responding to this part of the article that accidentally came out as a rant because i'm so passionate about virtualization.

    "What about ESX 4.0? What about the hypervisors of Xen/Citrix and Microsoft? What will happen once we test with 8 or 12 VMs? The tests are running while I am writing this. We'll be back with more. Until then, we look forward to reading your constructive criticism and feedback.

    Sorry, i meant to be more constructive haha...



  • JohanAnandtech - Sunday, May 24, 2009 - link

    "My statement is based on my own experience and findings. I can send you my benchmark comparisons if you wish. "

    Yes, please do. Very interested in to reading what you found.

    "I wasn't ranting at the article, its great for what it is, which is what the title represents. "

    Thx. no problem...Just understand that these things takes time and cooperation of the large vendors. And getting the right $5000 storage hardware in lab is much harder than getting a $250 videocard. About 20 times harder :-).


  • Bandoleer - Sunday, May 24, 2009 - link

    I haven't looked recently, but high performance tiered storage was anywhere from $40k - $80k each, just for the iSCSI versions, the FC versions are clearly absurd.

  • solori - Monday, May 25, 2009 - link

    Look at ZFS-based storage solutions. ZFS enables hybrid storage pools and an elegant use of SSDs with commodity hardware. You can get it from Sun, Nexenta or by rolling-your-own with OpenSolaris:

    http://solori.wordpress.com/2009/05/06/add-ssd-to-...">http://solori.wordpress.com/2009/05/06/add-ssd-to-...
  • pmonti80 - Friday, May 22, 2009 - link

    Still it would be interesting to see those central storage benchmarks or at least knowing if you will/won't be doing them for whatever reason.

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