I am replacing a KVM server with a ESXi server. I just installed ESXi 5.5u1 and added a data store. The new server has 4 SSD drives in RAID 6 using hardware RAID. When I added the data store VMware says that the store is non-ssd.

Is this normal? Obviously VMware is seeing the virtual disk exposed by the RAID card not the SSD's themselves. Should VMware be told these are solid state disks for best performance? or should that just be left to the RAID card? I’m mostly worried about TRIM.


Sure, you can do this.

You can tell ESXi that a particular datastore is comprised of SSDs.

Here's how:
Enabling the SSD option on SSD based disks/LUNs that are not detected as SSD by default (2013188)

You end up having to set a datastore claim rule similar to:

esxcli storage nmp satp rule add --satp SATP_TYPE --device naa.ID --option "enable_ssd"

This is a supported and normal solution. I have to do it for SSD datastores sitting behind HP RAID controllers.

TRIM isn't an issue. If you're using a hardware controller, let things be.

  • 1
    Great. I had found this article before posting my question but I was not sure if this was the "RIGHT" thing to do. I was afraid it might be sending SSD specific commands to the RAID controller which might not know what to do with them. I followed the instructions and the data store now shows up as SSD. The fact that this is the "normal" thing to do is key here for me. Thanks – digitaladdictions Apr 23 '14 at 20:17

The accepted answer works for vSphere 6 as well, and it works for both local and remote SSD drives either with JBOD or RAID configuration. The additional commands not mentioned in the answer are:

# esxcli storage core claimrule load
# esxcli storage core claimrule run
# esxcli storage core claiming reclaim -d <naa.ID>

Then you can test if you were successful using:

esxcli storage core device list -d <naa.ID> |grep SSD

This should return:

Is SSD: true

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