Loss of LAN

[Tim00]

I don't even know where to begin, so hopefully someone can help me there. 

Somewhat frequently (at least every 48 hours), I completely lose LAN.  All devices connected to opnsense are inaccessible and cannot connect to internet.  However, from an external network, I am able to connect via OpenVPN.  Doing this and rebooting resolves the problem.

There are no entries under any log that I can find in the webgui, including System->Log Files-> General, Configd,Webgui. 

A few notes, that may or may not be relevant:  this installation is on a VM on a Dell R710.  I was receiving some disk read errors on the host, which I attributed to a slow drive that ProxMox was installed on.  I replaced this with a more appropriate drive.  The read errors went away, but this issue has persisted. 

Where can start to diagnose this issue?

[ab5g]

Try a elimination based approach to troubleshooting

What version is the FW?
Do you have IPS turned on  ?
Can your LAN devices ping the local gateway on the firewall during the outage ?
Can you access the firewall UI from LAN during the outage ?
Isolate a DNS issue by pinging an internet IP instead of a domain
Firewall, Log, Live View >> What do you see when you have the outage.
Do you have any other packages installed like Sensei

[Tim00]

I figured I should close a loop on this.  It appears to have been a faulty battery on the RAID card.  Because of the faulty battery, the card defaulted to Write Through mode, resulting in significant (sometimes 30-50%) IO Delay.  Apparently, if this got too bad, the the OpnSense VM wouldn't entirely crash, but the LAN would disconnect and not come back on.  Since this really wasn't an issue with OpnSense, it didn't log anything.