Since vSAN does not support SSD disk as data disk, you will need to change how disks are presented in VMware ESXi server, if you run on SSD disks only. Remember that best practice for vSAN is that SSD cache is 10% of the total data disks capacity. In order to change disk presentation, log-in to your VMware ESXi server via SSH and list all of your local disks using the following command:
# esxcli storage core device list | grep mpx
You will get output like this:
mpx.vmhba1:C0:T2:L0 Display Name: Local VMware, Disk (mpx.vmhba1:C0:T2:L0) Devfs Path: /vmfs/devices/disks/mpx.vmhba1:C0:T2:L0 mpx.vmhba1:C0:T1:L0 Display Name: Local VMware, Disk (mpx.vmhba1:C0:T1:L0) Devfs Path: /vmfs/devices/disks/mpx.vmhba1:C0:T1:L0 mpx.vmhba1:C0:T0:L0 Display Name: Local VMware, Disk (mpx.vmhba1:C0:T0:L0) Devfs Path: /vmfs/devices/disks/mpx.vmhba1:C0:T0:L0 mpx.vmhba32:C0:T0:L0 Display Name: Local NECVMWar CD-ROM (mpx.vmhba32:C0:T0:L0) Devfs Path: /vmfs/devices/cdrom/mpx.vmhba32:C0:T0:L0
Identify the target disk via vSphere Web Client, select your ESXi server, click tab Manage, then click Storage in menu. Select Storage Adapter and in Devices, under Adapter Details identify your storage.
Once you have identified storage you want to present as NonSSD, note down its ID and then use the following command to change presentation type:
# esxcli storage nmp satp rule add --satp VMW_SATP_LOCAL --device mpx.vmhba1:C0:T1:L0 --option=disable_ssd # esxcli storage core claiming reclaim -d mpx.vmhba1:C0:T1:L0
Obviously, replace “mpx.vmhba1:C0:T1:L0” with your own ID.
To revert changes, use the following command:
# esxcli storage nmp satp rule remove --satp VMW_SATP_LOCAL --device mpx.vmhba1:C0:T1:L0 --option=disable_ssd # esxcli storage core claiming reclaim -d mpx.vmhba1:C0:T1:L0