Windows Server 2016 Tech Preview 2 Storage Spaces disk FriendlyName values on VMware Workstation are all the same

I was playing with Storage Spaces under Windows Server 2016 Tech Preview 2. As usual in virtual environment Storage Spaces was unable to detect MediaType correctly. When I went to fix it with a usual command “Set-PhysicalDisk -FriendlyName PhysicalDisk1 -MediaType SSD” it did not work because disk FriendlyName was not PhysicalDisk1. Instead it was “VMware, VMware Virtual S”. Actually all the disks had the same FriendlyName – “VMware, VMware Virtual S“.

Disk FriendlyNames before changing them

To fix this I assigned each disk unique FriendlyName and also fixed MediaType.

To change disk FriendlyName and MediaType I used command:
Set-PhysicalDisk -UniqueId “{8433bca0-314d-11e5-94f3-000c29b96d5e}” -NewFriendlyName “SSD1” -MediaType SSD

To get disk UniqueId values I used command:
Get-StoragePool Pool2 | Get-PhysicalDisk | Select FriendlyName,MediaType,UniqueId,Size

After changing the FriendlyNames and MediaTypes it was much more clearer which disk is SSD and which disk is HDD.

Disk FriendlyNames changed

How to estimate deduplication and compession ratios?

In my opinion the honest answer is that you can’t estimate. There is no good and accurate way to estimate deduplication and compression ratios because there are many variables that will affect the ratio. There are estimation tools available from different vendors but you will get most accurate numbers by testing different solutions with your actual data. I have tested several solutions and deduplication and/or compression ratio has varied between 2.5x to 8x.


  • Test different solutions – to understand how well different solutions work. Example solution #1 has dedupe ratio of 4 which looks good but solution #2 has dedupe ration 8 with same data.
  • Try to use the same test data during different tests so the results would be comparable.


  • Microsoft Windows Server 2012 R2 – built in post-process deduplication engine. Check this page for more information.
  • QuadStor software – inline deduplication and compression. Check this page for more information.
  • Nutanix Community Edition – has both deduplication and compression options.
  • All Flash Arrays – most AFA-s include deduplication and/or compression for data reduction. If you are interested of AFA-s most vendors can hook you up with POC equipment which you can use to test the solution. AFA vendors to check EMC, Pure Storage, Kaminario, SolidFire, etc.


Results will vary between different solutions. Deduplication works well for similar data (VDI, Server OS disks), compression works better for databases (Oracle, MSSQL). Deduplication ratio is also affected from deduplication chunk size – 512bytes, 4K, 8K, 16K, etc. Usually smaller chunk size results better ratio.

More info

More info about this topic can be found on following links.

Deduplication ratios – What should be included in the reported ratio?

Understanding Data Deduplication (SNIA)

Using a file as a device in ScaleIO

In most cases one would use the whole unformatted disk as a device for ScaleIO, but sometimes this is not possible. To use the free space from already partitioned disk ScaleIO sds component has a command line tool called create_file_storage. It is located in the ScaleIO sds component folder. Tool will create a pre-allocated file with specified size to a specified location.

Command to create file:

create_file_storage −−create_file −−size_gb <SIZE_IN_GB> −−file_name <FILE_NAME> 


create_file_storage −−create_file −−size_gb 120 −−file_name C:\scaleio_devices\

create_file_storage command line

When adding a devices for SDS specify the full path of the file as the “Path” for the device.

File as device


The “file as device” options allows to start consuming free space for ScaleIO from disks that have existing partitions and existing file systems.