If you haven’t already upgraded your Windows servers to Windows 2019, then you will probably be doing so soon enough. That means that it’s time to review the steps you take in building out your virtual machines (VMs). Are you running your VMs from a SAN? Then during this refresh, you should really take the time to consider using the VMware Paravirtual SCSI (PVSCSI) driver.

VMware Paravirtual (PVSCSI) adapters are high-performance storage adapters that can provide greater throughput and lower CPU utilization. They are best suited for environments where hardware or applications drive a very high amount of I/O throughput, such as SAN environments. PVSCSI adapters are not suited for DAS environments.“

VMware, https://kb.vmware.com/s/article/1010398

When building new VMs there are four options you can choose from for their SCSI controller. The default LSI Logic SAS driver that is automatically selected for you will work just fine in most environments. That said, when you want to guarantee maximum performance from your VMs you will need to use the PVSCSI. Why wouldn’t you want to allow your VMs their max performance? It’s simple enough to do. Heck, do it and make a “golden image” template so you can easily redeploy it if you don’t want to repeat the steps on each VM everytime. It’s just a couple of clicks now for better performance later. Here we go…

1. Launch the vSphere Client and log in to an ESXi host or vCenter Server.
2. Select create a new virtual machine.
3. In the vSphere Client, right-click on the virtual machine and click Edit Settings.
4. Click the Hardware tab.
5. Click Add.
6. Select Hard Disk.
7. Click Next.
8. Choose any one of the available options.
9. Click Next.
10. Specify the options you require. Options vary depending on which type of disk you chose.
11. Choose a Virtual Device Node and specify whether you want to use Independent mode. For data disks, choose a Virtual Device Node between SCSI (1:0)to SCSI (3:15). For a boot disk, choose Virtual Device Node SCSI (0:0) or choose the Virtual Device Node that boots in the order you require.
    
    Note: To set a disk to use Independent mode there must be no snapshots associated to the virtual disk, if there are existing snapshots commit them before changing the disk type.
     
12. Click Next.
13. Click Finish to complete the process and exit the Add Hardware wizard. A new disk and controller are created.
14. Select the newly created controller and click Change Type.
15. Click VMware Paravirtual and click OK.
16. Click OK to exit the Virtual Machine Properties dialog.
17. Power on the virtual machine.
18. Install VMware Tools. VMware Tools includes the PVSCSI driver.
19. If it is a new virtual disk, scan and format the hard disk within the guest operating system.