Virtualization Performance: Linux VMs on ESXi

We introduced our new vApus FOS (For Open Source) server workloads in our review of the Facebook "Open Compute" servers. In a nutshell, it a mix of four VMs with open source workloads: two PhpBB websites (Apache2, MySQL), one OLAP MySQL "Community server 5.1.37" database, and one VM with VMware's open source groupware Zimbra 7.1.0. Zimbra is quite a complex application as it contains the following components:

  • Jetty, the web application server
  • Postfix, an open source mail transfer agent
  • OpenLDAP software, user authentication
  • MySQL is the database
  • Lucene full-featured text and search engine
  • ClamAV, an anti-virus scanner
  • SpamAssassin, a mail filter
  • James/Sieve filtering (mail)

All VMs are based on a minimal CentOS 5.6 setup with VMware Tools installed. All our current virtualization testing is on top of the hypervisor which we know best: ESXi (5.0). CentOS 5.6 is not ideal for the Interlagos Opteron, but we designed the benchmark a few months ago. It took us weeks to get this benchmark working and repeatable (especially the latter is hard). For example it was not easy to get Zimbra fully configured and properly benchmarked due to the complex usage patterns and high I/O usage. Besides, the reality is that VMs often contain older operating systems. We hope to show some benchmarks based on Linux kernel version 3.0 or later in our next article.

We tested with five tiles (one tile = four VMs). Each tile needs seven vCPUs, so the test requires 35 vCPUs.

vApus FOS

The Opteron 6276 stays close to the more expensive Xeons. That makes the Opteron server the one with the best performance per dollar. Still, we feel a bit underwhelmed as the Opteron 6276 fails to outperform the previous Opteron by a tangible margin.

The benchmark above measures throughput. Response times are even more important. Let us take a look at the table below, which gives you the average response time per VM:

vApus FOS Average Response Times (ms), lower is better!
CPU PhpBB1 PHPBB2 MySQL OLAP Zimbra
AMD Opteron 6276 737 587 170 567
AMD Opteron 6174 707 574 118 630
Intel Xeon X5670 645 550 63 593
Intel Xeon X5650 678 566 102 655

The Xeon X5670 wins a landslide victory in MySQL. MySQL has always scaled better with clock speed than with cores, so we expect that clock speed played a major role here. The same is true for our first VM: this VM gets only one CPU and as result runs quicker on the Xeon. In the other applications, the Opteron's higher (integer) core count starts to show. However, AMD cannot really be satisfied with the fact that the old Opteron 6174 delivers much better MySQL performance. We suspect that the high latency L2 cache and higher branch misprediction penalty (20 vs 12) is to blame. MySQL performance is characterized by a relatively high amount of branches and a lot of accesses to the L2. The Bulldozer server does manage to get the best response time on our Zimbra VM, however, so it's not a complete loss.

Performance per watt remains the most important metric for a large part of the server market. So let us check out the power consumption that we measured while we ran vApus FOS.

vApus FOS Power Consumption

The power consumption numbers are surprising to say the least. The Opteron 6174 needs quite a bit less energy than the two other contenders. That is bad news for the newest Opteron. We found out later that some tinkering could improve the situation, as we will see further.

Benchmark Configuration Measuring Real-World Power Consumption, Part One
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  • geoxx - Friday, December 9, 2011 - link

    Sorry but neotiger is totally right, choice of benchmark sucks. We are not helped *at all* by your review.
    What company 32-core server is being used for 3D rendering, cinebench, file compression, truecrypt encryption??
    You benchmarked it like it was a CPU of the nineties for a home enthusiast.

    You are probably right pointing us to http://www.anandtech.com/show/2694 but your benchmarks don't reflect that AT ALL. Where are file compression, encryption, 3D rendering and cinebench in that chart?

    Even performances per watt is not very meaningful because when one purchases a 2-socket or 4-socket server, electricity cost is not an issue. Companies want to simplify deployment with such a system, they want this computer to run as fast as a cluster, in order not to be bound to cluster databases which are a PAIN. So people want to see scalability of applications to full core count on this kind of system, not so much performances per watt.

    Virtualization is the ONLY senseful benchmark you included.

    TPC as suggested is a totally right benchmark, that's the backend and bottleneck for most of the things you see in your charts at http://www.anandtech.com/show/2694 , and objection on storage is nonsense, just fit a database in ramdisk (don't tell me you need a database larger than 64GB for a benchmark), export as block device, then run the test. And/or use one PCI-e based SSD which you certainly have.

    http://www.anandtech.com/show/2694 mentions software development: how much effort does it require to set up a linux kernel compile benchmark?

    http://www.anandtech.com/show/2694 mentions HPC: can you set up a couple of bioinformatics benchmarks such as BLAST (integer computation, memory compare), GROMACS (matrix FPU computations) and Fluent? Please note that none of your tests includes memory compares and FPU which are VERY IMPORTANT in HPC. Gromacs and fluent would cover the hole. Bioinformatics is THE hpc of nowdays and there are very few websites, if any, which help with the choice of CPUs for HPC computing.

    For email servers (37%!) and web servers (14%) also I am sure you can find some benchmarks.
  • Iketh - Tuesday, November 15, 2011 - link

    I'm not sure how the discovery of cores running in their power-saving state for far too long is anything new. My 2600k refuses to ramp up clocks while previewing video in a video editor even though a core is pegged at 100%. If I intervene and force it to 3.4ghz, preview framerate jumps from 8 fps to 16fps.

    This has been happening for YEARS! My old quad Phenom 2.2ghz did the exact same thing!

    It's extremely annoying and pisses me off I can't benefit from the power savings, let alone turbo.
  • MrSpadge - Tuesday, November 15, 2011 - link

    Sounds like you're running linux or some other strange OS, then. Or you may need a bios update. Generally Intel has its power management quit under control. In the AMD camp physical power state switches often take longer than the impatient OS expects, and thus average frequency is hurt. This was pretty bad for Phenom 1.

    MrS
  • Iketh - Tuesday, November 15, 2011 - link

    win7 home premium x64 and the phenom was with xp 32bit... i haven't found another scenario that causes this, only streaming video that's rendered on-the-fly
  • Zoomer - Wednesday, November 16, 2011 - link

    You have a 2600k and aren't running it at 4+ GHz?
  • Iketh - Wednesday, November 16, 2011 - link

    4.16 @ 1.32v when encoding, 3.02 @ 1.03v for gaming/internet
  • haplo602 - Wednesday, November 16, 2011 - link

    you do know that Linux did not have any problems with Phenom I power management unlike Windows ? Same is not with BD. Linux benchmarks look quite different from Windows and the gap is not that dramatic there.
  • BrianTho2010 - Tuesday, November 15, 2011 - link

    This whole review, the only thought I have is that there are no sandy bridge chips in it. When SB based Xeon chips come out I bet that Interlagos will be completely dominated.
  • Beenthere - Tuesday, November 15, 2011 - link

    Not really. SB chips don't fit in AMD sockets. AMD's installed customer base like the significant performance increase and power savings by just plugging in a new Opteron 6200/4200.
  • C300fans - Tuesday, November 15, 2011 - link

    It will. 2x6174 (24 cores) perform quite similar to 2x6274(32 cores). WTF

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