ESXi allows operating systems to auto-detect VMDKs residing on SSD datastores as SSD devices.
To verify if this feature is enabled, guest operating systems can use standard inquiry commands such as SCSI VPD Page (B1h) for SCSI devices and ATA IDENTIFY DEVICE (Word 217) for IDE devices.
For linked clones, native snapshots, and delta-disks, the inquiry commands report the virtual SSD status of the base disk.
Operating systems can auto-detect a VMDK as SSD under the following conditions:
Detection of virtual SSDs is supported on ESXi 5.x hosts and Virtual Hardware version 8 or later.
Detection of virtual SSDs is supported only on VMFS5 or later.
If VMDKs are located on shared VMFS datastores with SSD device extents, the device must be marked as SSD on all hosts.
For a VMDK to be detected as virtual SSD, all underlying physical extents should be SSD-backed.