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Lately I’ve been running some Storage Spaces Direct labs on VMware workstation. Part of doing labs means testing things until something breaks and as a countermeasure I tend to create snapshots frequently. Now this led me to an issue that I haven’t seen anyone write about online.
It turns out that creating snapshots messes with the detection of the Windows storage MediaType.
When there are no snapshots present everything works as expected. The CMDlet Get-Physical disk returns the MediaType that is actually in use. In my case this is SSD.
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DeviceId FriendlyName SerialNumber MediaType CanPool OperationalStatus HealthStatus Usage Size -------- ------------ ------------ --------- ------- ----------------- ------------ ----- ---- 0 VMware, VMware Virtual S 6000c293a1649c89eb9a0516964d8213 SSD False OK Healthy Auto-Select 60 GB 1 VMware, VMware Virtual S 6000c2988a75a88690a5722d984ba03e SSD True OK Healthy Auto-Select 8 GB 2 VMware, VMware Virtual S 6000c2901ba3cfe177b5d370752cd0fd SSD True OK Healthy Auto-Select 8 GB 3 VMware, VMware Virtual S 6000c298e5b2aa53f3f14672fe2ffd98 SSD True OK Healthy Auto-Select 8 GB 4 VMware, VMware Virtual S 6000c2931f4285437978e67c130cb31a SSD True OK Healthy Auto-Select 8 GB |
However when you create a snapshot and powercycle the VM the CMDlet returns a MediaType of Unspecified.
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DeviceId FriendlyName SerialNumber MediaType CanPool OperationalStatus HealthStatus Usage Size -------- ------------ ------------ --------- ------- ----------------- ------------ ----- ---- 0 VMware, VMware Virtual S 6000c293a1649c89eb9a0516964d8213 Unspecified False OK Healthy Auto-Select 60 GB 1 VMware, VMware Virtual S 6000c2988a75a88690a5722d984ba03e Unspecified True OK Healthy Auto-Select 8 GB 2 VMware, VMware Virtual S 6000c2901ba3cfe177b5d370752cd0fd Unspecified True OK Healthy Auto-Select 8 GB 3 VMware, VMware Virtual S 6000c298e5b2aa53f3f14672fe2ffd98 Unspecified True OK Healthy Auto-Select 8 GB 4 VMware, VMware Virtual S 6000c2931f4285437978e67c130cb31a Unspecified True OK Healthy Auto-Select 8 GB |
I tested this with version 15.5.2 build-15785246 of VMware workstation both with snapshots with the VM powered on and powered off. I also tested the same procedure on vSphere but did not have the same issue there.
This issue is something to be mindful of when creating S2D clusters as it requires to be the MediaTypes to be the same across nodes. In my case I only created a snapshot on the first node and the cluster validation script returned an error. Removing the snapshot and powercycle the VM. Simply rebooting won’t do you any good!