What is Storage Controllers in VMware VSphere?

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Virtual Machines in VMware vSphere environment required a Storage Controller to access the virtual disks, CD/DVD-ROM, and SCSI devices. These storage controllers added by default when you create a virtual machine. You can modify these controllers in a virtual machine.

There are multiple types of storage controller available to use for a virtual machine.

  • BusLogic Parallel
  • LSI Logic Parallel
  • LSI Logic SAS
  • VMware Paravirtual SCSI
  • AHCI, SATA
  • IDE
  • NVMe

How Storage Controller Technology Works

Storage controllers appear to a virtual machine. Most of them are SCSI (or SAS) based including BusLogic Parallel, LSI Logic Parallel, LSI Logic SAS, and VMware Paravirtual SCSI.

Storage controller such as NVMe is a standardized protocol designed specifically for high-performance multi-queue communication with NVM devices. VMware ESXi supports the NVMe protocol to connect to local and networked storage devices(NAS).

Each virtual machine can have a maximum of four SCSI controllers. The default SCSI controller is numbered as 0. When you create a virtual machine, the default hard disk is assigned to the default SCSI controller 0 at the bus node (0:0). If you add more storage controllers, they are numbered sequentially 1, 2, and 3.

The more storage controller you use, virtual machine can be able to handle more IO request for the disk.

Each virtual machine can have a maximum of two IDE controllers, four SCSI controllers, four SATA controllers, and four NVMe controllers.

Storage Controller Limitations

The Storage controllers have the following requirements and limitations:

  • LSI Logic SAS and VMware Paravirtual SCSI are available for virtual machines with ESXi 4.x and later compatibility.
  • AHCI SATA is available only for virtual machines with ESXi 5.5 and later compatibility.
  • NVMe is available only for virtual machines with ESXi 6.5 and later compatibility.
  • BusLogic Parallel controllers do not support virtual machines with disks larger than 2TB.
  • Disks on VMware Paravirtual SCSI controllers might not experience optimal performance gains if they have snapshots or if the host’s memory is overcommitted.
  • IDE does not provide disk hot add or disk space hot-add.

Storage Controller Compatibility

The compatibility of a storage controller is important to support the virtual machine requirement. If it is not compatible then BIOS firmware can cause operating system boot problems. So choose it wisely. You may refer below chart to get the right storage controller for your need:

Storage Controller
Storage Controller Compatibility

Steps To Add Storage Controller

We will explain the simple steps to add a storage controller to the virtual machine.

  1. Right-click the virtual machine and select Edit Settings.
    • To locate a virtual machine, select a datacenter, folder, cluster, resource pool, host, or vApp.
    • Click the Related Objects tab and click Virtual Machines.
  2. On the Virtual Hardware tab, select SCSI Controller from the New device drop-down menu and click Add.
  3. Expand New SCSI Controller, and select the type of sharing in the SCSI Bus Sharing drop-down menu.
  4. Select the controller type from the drop-down menu.
  5. Click OK.

Reference:

VMware SCSI Controller Configuration

Starwind

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