Solved

Found some VMs with IDE bus type for disks, why?

  • 18 February 2022
  • 3 replies
  • 184 views

Badge +1

Hello everyone,

Someone before me in my current job created a couple of VMs in AHV with IDE bus type for their disks instead of SCSI. Just a quick glance of the documentation I found this:

AHV does not leverage a traditional storage stack like ESXi or Hyper-V. All disk(s) are passed to the VM(s) as raw SCSI block devices.

So my question is, why would someone decide to create IDE disks? Am I missing something? I know it’s common practice for CD-ROM drives, but not storage disks. No wonder I noticed a really bad performance on those servers recently.

icon

Best answer by mikkisse 20 February 2022, 16:53

View original

This topic has been closed for comments

3 replies

Userlevel 2
Badge +3

Nutanix best practices dictate that regular virtual disk drives are configured on the SCSI bus, and CD-ROM drives are configured on the IDE bus. While regular disk drives can be configured on the IDE bus, it is possible that performance degradation may be seen on the drive.

If this performance impact is deemed acceptable, then this check can be ignored

NCC health check uvm_ide_disk_check determines if any vDisks or VMDKs are attached to any guest VMs using the IDE controller. The IDE controller is subject to lower performance because of its low queue depth in relation to SCSI.
 

Reference Link: https://portal.nutanix.com/page/documents/kbs/details?targetId=kA03200000098MkCAI

Userlevel 4
Badge +3

Some of the very legacy systems can’t work with scsi and ide is the one and only option. Faced with that when I needed to launch RHEL4 system :slight_smile:

Userlevel 2
Badge +3

I would agree with “mikkisse”. However, please validate UVMs before making any changes to production enviroment.