vSAN Operations: Local Disk Identification

If a local disk on a server fails (or is about to fail) the storage controller will notice this and will inform the vCenter via CIM. The failed disk should then be indicated both in the vCenter and on the disk LED. The disk identification will in these circumstances be the same on a vSAN host as on any standard ESXi host.

The problem is when the vSAN cluster itself discovers a 'problematic' disk. Cormac Hogan blogged about this in his VSAN 6.2 Part 10 ā€“ Problematic Disk Handling post. The disk is here considered problematic by vSAN but not necessarily by the RAID controller. The problematic disk will therefore be indicated in the vCenter but not on the disk LED.

It will in this scenario be up to the virtualization admin to inform the datacenter staff, which disk to replace. The easiest way to do this is for the virtualization admin to turn on the disk LED manually from the web client or the command line. But, as I indicated in my blog post Turn on Disk LED on HP P840 Storage Contoller, this is not always possible.

In these cases, the virtualization admin will have to manually figure out which disk to replace. This can be done in the following way (I've tested this on a few occasions and it was consistent for me, I can't guarantee that it will always work though):

  1. Find the disk that need to be identified by accessing Manage > Storage > Storage Devices from the ESXi host.

  2. Highlight the disk that needs to be identified and choose Paths from Device Details.

  3. Find the target number (the number after 'T') of the disk in the Runtime Name and make a note of this.

Disk Runtime Name

  1. Find the drive bay number by accessing the ESXi host > Monitor > Hardware Status > Sensors. Expand Storage and find the right disk. The disk number is the target number + 1. If the target was 0 the right disk would be Disk 1, and find the bay the disk is connected to (in the example this is Bay 5):

Disk Bay Number

It's fairly likely that mistakes are made identifying a disk using this method. The virtualization engineer would have to find the disk, inform the datacenter staff, and they would then have to identify the right bay.

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