What is SCSI Controller in Dedicated Servers / VM?

[Helposoft Staff]

A SCSI (Small Computer System Interface) controller is a hardware interface that allows computers to communicate with peripheral devices, such as hard drives, CD-ROM drives, printers, and scanners. In the context of virtualization and creating virtual machines (VMs), a SCSI controller plays an important role in managing virtual disks and other storage devices. Here's a breakdown of its key aspects:

Functionality​

1. Communication:
   • Acts as an intermediary between the CPU and storage devices.
   • Sends commands from the operating system to the storage devices and retrieves data from them.
2. Performance:
   • SCSI controllers are known for high-speed data transfer and efficient multitasking.
   • They support a wide range of devices and offer robust performance.
3. Virtualization:
   • In a virtual machine, the SCSI controller manages virtual disks, which are stored as files on the host machine.
   • Provides the VM with access to storage as if it were a physical hard drive.

Types of SCSI Controllers in Virtualization​

1. LSI Logic:
   • Often used in virtual machines for compatibility with various operating systems.
   • Suitable for general-purpose workloads.
2. VMware Paravirtual:
   • Optimized for virtual environments.
   • Provides higher performance and lower CPU usage compared to other types.
   • May require specific drivers for the guest operating system.
3. VirtIO SCSI:
   • Designed for KVM (Kernel-based Virtual Machine) environments.
   • Offers improved performance and flexibility.
   • Requires VirtIO drivers in the guest operating system.

Configuration in Proxmox​

When setting up a VM in Proxmox, you can choose the type of SCSI controller to use:

• Bus/Drive: Determines how the virtual disks are connected to the SCSI controller.
• SCSI Controller Type: Options like LSI, VMware Paravirtual, and VirtIO SCSI.
• Performance: Choosing the right controller can impact the performance of the VM, especially for I/O-intensive applications.

Advantages of SCSI Controllers​

• High Performance: SCSI controllers are known for their speed and efficiency.
• Multiple Devices: Can handle multiple devices on a single controller.
• Flexibility: Supports a wide range of devices and configurations.

In summary, a SCSI controller in a virtualized environment manages virtual disks and other storage devices, providing the virtual machine with access to storage as if it were physical hardware. Selecting the appropriate SCSI controller type can influence the performance and compatibility of the virtual machine.