I was welcomed to my Monday morning with an interesting Solarwinds alert for one of my ESXi hosts: Direct, Local USB Direct-Access (mpx.vmhba32:C0:T0:L0) has a current status of Critical. Awesome! I love it when USB devices fail.

But wait, something didn’t add up correctly. It was my understanding that none of my hosts are USB install. Our standard is either local SSD, SD cards or in the case of Nutanix, SATADOM’s. So why am I getting a USB failure for my host? Let’s take a look.

Under Storage Adapters, sure enough there’s a vmhba32 under “USB Storage Controller” with a Path status of “Dead”. Again, these aren’t USB installs… or are they?

The first thing we need to determine is the path of our boot disk. We can accomplish this with:

ls -la /bootbank

That should output something similar to:

/bootbank -> /vmfs/volumes/d73c2987-b916392d-098d-ab39b98d0fd1

With the path of our boot disk, we can now find the disk ID:

vmkfstools -P /vmfs/volumes/d73c2987-b916392d-098d-ab39b98d0fd1

Which will output something like:

vfat-0.04 file system spanning 1 partitions.
File system label (if any):
Mode: private
Capacity 261853184 (63929 file blocks * 4096), 93765632 (22892 blocks) avail
UUID: d73c2987-b916392d-098d-ab39b98d0fd1
Partitions spanned (on "disks"): 
mpx.vmhba32:C0:T0:L0:6
Is Native Snapshot Capable: NO

And now we can get some much needed details using the disk ID and esxcli:

   esxcli storage core device list |grep -A27 ^mpx

   Display Name: Local USB Direct-Access (mpx.vmhba32:C0:T0:L0)
   Has Settable Display Name: true
   Size: 15280
   Device Type: Direct-Access
   Multipath Plugin: NMP
   Devfs Path: /vmfs/devices/disks/mpx.vmhba32:C0:T0:L0
   Vendor: Dell Com
   Model: Internal Dual SD
   Revision: 0110
   SCSI Level: 2
   Is Pseudo: false
   Status: on
   Is RDM Capable: false
   Is Local: true
   Is Removable: true
   Is SSD: false
   Is Offline: false
   Is Perennially Reserved: false
   Queue Full Sample Size: 0
   Queue Full Threshold: 0
   Thin Provisioning Status: unknown
   Attached Filters:
   VAAI Status: unsupported
   Is Local SAS Device: false
   Is Boot USB Device: false

So there you have it. The host is leveraging dual internal SD cards! Thank you vCenter for trying to confuse me.