VMware vSphere

 View Only
  • 1.  use Iometer to measure throughput of virtual disk

    Posted Jan 27, 2012 05:51 PM

    I am looking to use Iometer to measure the throughput of a virtual disk. IBM claim that their VAAI drivers will increase the throughput of virtual disks by 30% using block zeroing. The plan is to use IOmeter to generate a load, and measure the throughput on an ESXI host with and without VAAI drivers. A test VM will be used with a windows guest.

    IBM claim they measured the results using  IOmeter set up with 1MB sequential writes on a virtual disk.

    This is the first time I have used IOmeter. I plan to use Iometer with the following settings:

    Transfer request size: 1MB

    100% sequential distribution

    100% write

    I plan to measure the throughput of the virtual disk, using the following counter on the vcenter client:

    virtualdisk/write rate kbps

    I would prefer to do a discreet test that will not put too much of a load on the SAN, as the server I am testing will be using a production SAN. I tried using IOmeter on my desktop with these settings. It generated load up to 38MB/second at its peak.

    Any tips on doing a discreet test on a production LAN, plus validation of the testing plan is appreciated.



  • 2.  RE: use Iometer to measure throughput of virtual disk

    Posted Oct 09, 2012 01:36 AM

    I realize this is an old post, but I thought I would respond because I too was recently testing Iometer on a production IBM SAN (SVC) using 1MB block sizes, 100% write, 100% sequential.  I was testing the round robin policy to see how much throughput I could generate on a 4-port HBA blade server.  I was able to hit sustained speed over 1000MB/sec, and peaked at 1330.

    The trick to doing this on a production SAN - if you are really concerned about hitting peak numbers only - is to configure a very small hard drive size in iometer, and only run the test for a few seconds at a time.  I used a 660MB disk size, and my test never went beyond 5-10 seconds.  This is nowhere near an ideal test, but it will tell you your maximum throughput of the storage area network, since most all of this data will be satisfied on the SAN cache.  I wanted to see how much data my 4GB FC SAN network could push compared to the fixed paths I was using.  I was able to get a 300% increase in throughput by switching to round robin and by installing another HBA.