I've been using unraid for about 4 months now and recently my drives have been getting disconnected. 
This is my hdd enclosure I use to have my parity and 2 disks used all 12tb. I have it set to register each hdd as its own device instead of using the raid feature. 

Also everyday I find that the device has just turned off in a seemingly random fashion. 
Here is the syslog.txt

I have to manually turn it back on each time and start the array back up.

If you need anymore information to help please let me know.. I've tried to fix it myself but I'm pretty stuck
 

syslog.txt

The syslog starts afresh every time the system is booted.

 

The syslog in the diagnostics is the RAM copy and only shows what happened since the reboot.   It could be worth enabling the syslog server to get a log that survives a reboot so we can see what happened prior to the reboot. The mirror to flash option is the easiest to set up, but if you are worried about excessive wear on the flash drive you can put your server’s address into the Remote Server field.

19 minutes ago, itimpi said:

The syslog starts afresh every time the system is booted.

 

The syslog in the diagnostics is the RAM copy and only shows what happened since the reboot.   It could be worth enabling the syslog server to get a log that survives a reboot so we can see what happened prior to the reboot. The mirror to flash option is the easiest to set up, but if you are worried about excessive wear on the flash drive you can put your server’s address into the Remote Server field.

Alright just enabled it once it crashes again I'll repost the syslog server

Are you using the eSATA or USB connection?

Update: It appears to have been power failure from my home circuits. It was whenever someone would run the microwave on the same circuit it would kill power for a few seconds and restore it without popping a breaker. 

 

Get an UPS