How to debug issues with Debian 9.11 on Beaglebone Black?

Question

I am running Debian 9.11 (4.14.108-ti-r124) on BBB and it runs fine for about a week and then Bash no longer can find commands and it throws errors upon every command. Commands result in one of two errors depending upon the command:

-bash: /bin/ping: Input/output error
-bash: reboot: command not found

What are some approaches to determining the root cause for this? Once the machine begins to exhibit these symptoms no further debugging is possible.

My gut says that the pipes Bash uses are getting closed or corrupt but I have not seen any reference to that in Debian issues for Stretch.

Update: The time between issues seems to be shrinking. After three days:

debian@radius:/opt$ uptime 
-bash: /usr/bin/uptime: Input/output error

Answer 1

It turns out the SD card was failing and the failure was exacerbated by having to forcefully power down the server due to non-responsiveness. Kind of a death spiral. I will try using EVO cards to see if the show longer life.