Premium SSDs Show In Server 2019 as HDDs RRS feed

  • Question

  • Hi everyone,

    I'm creating a lab supporting a migration to Azure where we intend on using Storage Spaces Direct (S2D) for file storage among other things.  I guess you could refer to it as a virtual hyper-converged platform.

    Now, I'm very interested in tiered storage and the caching capabilities of S2D, and so I've created a 4 node cluster.  Each node has:

    2 x 1TB Premium SSDs (Managed)

    8 x 1TB Standard HDDs (Managed)

    The problem I'm facing is that regardless of the type of disk, they are presented to the operating system with the same model.  Ie. Msft Virtual Disk.  The Get-PhysicalDisk cmdlet shows all disks as HDDs.  So, when I enable the cluster for S2D, it is reported that no disks could be identified/claimed for cache.  This means that creating a virtual disk / volume - heck knows what the performance is going to be between one volume and another.

    I have managed to set the MediaType to SSD manually, and the Usage to Journal for the SSDs using Set-PhysicalDisk, but I have no real way of knowing whether the SSDs are infact being used for cache.  The Get-StorageSpacesDirect cmdlet shows cache as enabled, but shouldn't the disks be presented to the operating system differently?  I'm using Server 2019 - does this make a difference? I doubt it.

    Any advice would be much appreciated.

    Wednesday, July 10, 2019 2:18 PM

All replies

  • JamieEvansAllpay

    Thanks for the questions, I raised these concerns internally to the team. I'll follow up with you as soon as I hear back any clarifications.

    Wednesday, July 10, 2019 4:24 PM
  • Hello Jamie,

    Devices actually present themselves with a media type.  If the SSDs are showing as HDD, then it may be they need a firmware update or change.  I'm not aware of a known issue where S2D shows a device as HDD where it presents itself as SSD, it's always been firmware (so far).

    I'd recommend seeing if the SSD's are on the Windows Server hardware catalog, and if so, if they have the SDDC AQ.  That AQ indicates it's been validated to function correctly for S2D.  Server catalog listing is the minimum supported qualification.  

    This page has all the hardware requirements, and links to the Windows Server hardware catalog.


    The method to identify what disks are used as cache devices by S2D is Get-PhysicalDisk and look to see if it's "automatic" or "journal".  Journal means it's being used as a cached device. Cryptic, I know.

    This page has information about the cache device usage and how to determine they are cache:


    I hope this helps,

    Steven Ekren

    Senior Program Manager

    Windows Server


    This posting is provided "AS IS" with no warranties, and confers no rights.

    Wednesday, July 10, 2019 4:36 PM
  • Jamie,

    I re-read your post and realized you are deploying in Azure, and not on physical hardware.

    All disks from any cloud or private cloud platform show up in the VM as HDD.  

    There is no Cache layer when deploying in a cloud.  You need all Premium disks.


    This posting is provided "AS IS" with no warranties, and confers no rights.

    Wednesday, July 10, 2019 4:45 PM
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    Wednesday, July 24, 2019 8:21 AM