Add a SCSI Controller in the vSphere Web Client

Many virtual machines have a SCSI controller by default, depending on the guest operating system. If you have a heavily loaded virtual machine with multiple hard disks, you can add up to three additional SCSI controllers to assign the disks to. When you spread the disks among several controllers, you can improve performance and avoid data traffic congestion. You can also add additional controllers if you exceed the 15-device limit for a single controller.

Prerequisites

• Verify that you have the Virtual machine.Configuration.Add or remove device privilege on the virtual machine.
• Verify that you are familiar with storage controller behavior and limitations. See SCSI and SATA Storage Controller Conditions, Limitations, and Compatibility.

Procedure

1. Right-click a virtual machine in the inventory and select Edit Settings.
2. On the Virtual Hardware tab, select SCSI Controller from the New device drop-down menu and click Add.
   The controller appears in the Virtual Hardware devices list.
3. On the Virtual Hardware tab, expand New SCSI Controller, and select the type of sharing in the SCSI Bus Sharing drop-down menu.

   Option	Description
   None	Virtual disks cannot be shared by other virtual machines.
   Virtual	Virtual disks can be shared by virtual machines on the same ESXi host. Select Thick provision eager zeroed when you create the disk.
   Physical	Virtual disks can be shared by virtual machines on any ESXi host. Select Thick provision eager zeroed when you create the disk.

4. Select the controller type from the drop-down menu.
   Do not select a BusLogic Parallel controller for virtual machines with disks larger than 2TB. This controller does not support large capacity hard disks.
5. Click OK.

What to do next

You can add a hard disk or other SCSI device to the virtual machine and assign it to the new SCSI controller.