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.

Procedure

  1. Right-click a virtual machine in the inventory and select Edit Settings.
  2. On the Virtual Hardware tab, add a new SCSI controller.
    Client Steps
    vSphere Client Click the Add New Device button and select SCSI Controller from the drop-down menu.
    vSphere Web Client
    1. Select SCSI Controller from the New device drop-down menu at the bottom of the wizard.
    2. Click Add.
    The controller appears in the Virtual Hardware devices list.
  3. From the Change Type drop-down menu, select the controller type.
    Do not select a BusLogic Parallel controller for virtual machines with disks larger than 2TB. This controller does not support large capacity hard disks.
  4. 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.
  5. Click OK.

What to do next

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