External USB Drives Disconnecting from VM

[DVScuba]

Hi there. I'm losing my mind a little (in addition to a few TB of Music, Home Video and important data {facepalm}).

 

I've been running XPE DSM3615xs on ESXi for the past several months without any issues. Suddenly I was unable to access my PMS (Plex) last week. I found my external USB enclosure in a power-save state. i.e. The host USB port has shut down and the 4x 3TB drives in the enclosure are not spinning once the enclosure detected "disconnect from PC". After much trial and error, I discovered that booting ESXi and leaving it alaone, the external USB drives spin as expected and reachable by ESXi. Starting the DSM VM usually works OK for a few minutes and I can even launch the built in file manager (File Station). The DSM reports it is in the middle of Data Scrubbing. Sometime shortly thereafter, the drives stop being accessed and then spin down. The enclosure goes into "USB disconnected" mode and the DSM is unrecoverable.

 

In the short time I have access to the DSM, I have verified all power saving features are disabled (I believe). I seem to get about 6 minutes of uptime and the drives get disconnected. The accessible uptime is much less than 6 minutes. The DSM is now unusable and non-responsive. As soon as I shut down the VM in ESXi, the drives spin up again and are accessible via ESXi after a few rescans of the vmfs. Occasionally, the ESXi host becomes non-responsive for a while but is eventually reachable again.

 

My current hardware:

Asus VM42 Vivo PC - Celeron 2957U - 1.4GHz with 8GB RAM (hugely under powered but functional for my needs)

ESXi 6.7.0 - Build 14320388

DSM3615xs 6.2.2 update 4

SATA WD 500GB HDD w/ESXi and datastore1

Mediasonic HF2-SU3S2 USB3 w/4x Seagate Barracuda 3TB drives as USB-Datastore

 

Attempts at reading/assembling the drives using mdadm were fruitless.

Does anyone here have any ideas what to check? I don't seem to be catching anything in the logs 

 

Thanks for even thinking about helping.

 

DV