Andy Fox | 31 January 2013
Sometimes supported SSDs (Solid-State Drives) do not appear in the vSphere Client or Web Client as an SSD, but instead as unknown or Non-SSD. It is possible to use storage claim rules to alter this behaviour, to be able to use the ESXi host cache feature in ESXi 5.0 and above.
To start with, it is important to identify the device that
is being reported incorrectly.
As you can see from the vSphere Client above, the datastore created as SharedSSD is reported as Non-SSD.
We need to identify the device that this datastore has been created on; one possible way would be to go into the properties of the datastore, and then enter the manage paths screen as shown below.
Notice that the SATP (Storage Array Type Plugin) used for this device is VMW_SATP_DEFUALT_AA, we will need this with the device id.
We can then right click on the path and copy the name to the clipboard. In this case that would contain all the detail after Name: in the lower window. The only detail required is in this case the iSCSI t10 number.
(Although in this example we have already created a datastore on the device, it would be possible to configure a device that does not currently have a datastore as SSD except we would need to identify the device via the storage adapter.)
Once we have the device id, and SATP we can than use the esxcli command line tool (found in the ESXi shell, and vCli and vMa) to configure a claim rule.
The first setup is to create the claim rule with the required optional parameter to enable SSD.
The next step is to ensure that the claim rule has been added.
Notice that the claim rule previously entered is displayed as a result of the command.
Now we need to reclaim all claim rules to ensure that SSD is now enabled for this device.
Notice that in this case it was unable to unclaim the path. This can happen sometimes, and is easily fixed with a reboot of the host.
If you do not get the unable to reclaim message detailed above, you can now confirm that the rule has been applied and that the device is now seen as SSD.
As you can see in the above, the value for Is SSD: is true.
You should now see the datastore listed as SSD in the client.
It is also possible to use this method to allow the use of SSD for host caching when using a nested setup for testing.