Leverage VM Fleet Testing the Performance of Storage Space Direct

Back to 2 years ago, when I worked with Lenovo COSN team to ship their public cloud based on Windows Server 2012 R2, System Center 2012 R2 and Windows Azure Pack, we worked out a test procedure and a set of test scripts to validate the cloud platform. In order to simulate IO intensive workload, we deployed a bunch of VMs with auto logon scripts. Those auto logon scripts use fio to generate IO right after VM provisioned and started.

Now the project Diskspd (https://github.com/microsoft/diskspd) includes a set of scripts called VM Fleet (https://github.com/Microsoft/diskspd/tree/master/Frameworks/VMFleet), which use the similar mechanism to test the performance of Storage Space Direct.

In this post, I will demonstrate how I use the VM fleet to test the performance of my Hyper-Converged Cluster.

First of all, I deployed a 3-node Storage Space Direct Cluster. Here are the configurations of the testing machines.

DELL R720 (ECGCAT-R4-22, ECGCAT-R4-24, ECGCAT-R4-26)

  • CPU: E5-2650
  • Memory: 192GB
  • Boot Drive: H710 with 4 15K 600GB SAS HDDs (RAID10)
  • Data Drive: Micron P420m 1400GB
  • NIC: Chelsio T580 40Gb (RDMA capable)

After running Enable-ClusterS2D , I run the following cmdlet to create 3 CSVs, one for each node.

Get-ClusterNode |% {New-Volume -StoragePoolFriendlyName S2D* -FriendlyName $_ -FileSystem CSVFS_ReFS -Size 600GB -PhysicalDiskRedundancy 1}

Then run the cmdlet below to create an addition CSV to store scripts, tools, image and results.

New-Volume -StoragePoolFriendlyName S2D* -FriendlyName collect -FileSystem CSVFS_ReFS -Size 138GB -PhysicalDiskRedundancy 1

Then I downloaded Diskspd with VM Fleet from https://github.com/microsoft/diskspd. Copy the VMFleet folder to the one of the node in the above cluster (in my case, I copied it to D:\) and run the script from that node.

.\install-vmfleet.ps1 -source D:\VMFleet

Download the latest Diskspd from http://aka.ms/diskspd and copy the DISKSPD.exe into the folder C:\ClusterStorage\Collect\Control\Tools.

Prepared a Server Core VHD with the following steps if you don’t have one.

  1. I used Convert-WindowsImage.ps1 (https://gallery.technet.microsoft.com/scriptcenter/Convert-WindowsImageps1-0fe23a8f) to convert a Windows Server 2016 WIM image to a Server Core VHD.
  2. Use the above VHD to start a VM and set the initial password. (In my case, I use the password User@123.)
  3. Shutdown the VM (DON’T syspreped the  VM.)
  4. Copy the VHD to C:\ClusterStorage\Collect\. (In my case, the VHD is ENGWS2016COREG2VM.vhdx.)

Run the following script from folder C:\ClusterStorage\Collect\Control\. It created 10 VMs in each node. The step might  take from minutes to hours. It depends on how many VMs you will provision and hardware performance.

.\create-vmfleet.ps1 -basevhd "C:\ClusterStorage\Collect\ENGWS2016COREG2VM.vhdx" -vms 10 -adminpass User@123 -connectpass User@123 -connectuser "infra\administrator" -nodes "ECGCAT-R4-22","ECGCAT-R4-24","ECGCAT-R4-26"

I used the script below to change the VM configuration to 8 v-cores and 16GB static memory.

.\set-vmfleet.ps1 -ProcessorCount 8 -MemoryStartupBytes 16GB -DynamicMemory $false

Run script below to start all the VMs


You may check the console of one or more VMs and make sure there is no error.


Monitor the storage performance by running script below.



Last but the most important, you may stress IO by the script below. Here is an example, all the VMs run Diskspd to test 4KB 100% read random IO for 5 minutes (2 thread, QD=40).

.\start-sweep.ps1 -b 4 -t 2 -o 40 -w 0 -d 300


You may also test other IO profile like 4KB random read/write mixed IO (R/W: 70/30), 2 thread, QD=20 with the cmdlet below.

.\start-sweep.ps1 -b 4 -t 2 -o 20 -w 30 -d 300





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