Hi all! I've been struggling with a problem with my Unraid server (currently on 6.6.6) for a while now. Basically, from a fresh power up, it works normally. I use it primarily for Plex. After a few days, I can no longer transfer any files to it (it says its read-only), and my Plex clients can no longer see the server. I can still access it via the web interface, but it no longer works until I do another reboot. I've attached the diagnostic zip here. Anyone seen this before? Thanks for the help!

tower-diagnostics-20190414-1218.zip

First thing, that I saw was that you cache drive (sdf) is throwing up a ton of errors in your syslog.  The first error that I found for this drive was on April 1st.  There is no SMART report for it in the Diagnostics file.  I noticed that it was formatted BTRFS.  I do not use BTRFS but there are some folks who do.  I hope that they will chime in with some advice.  

Thanks for the reply. I was wondering if I might be having issues with my cache drive, and I considering just swapping it out. I figured I'd check if it was something more simple first. 

Cache drive dropped offline:

Apr  1 22:04:27 Tower kernel: ata5.00: status: { DRDY }
Apr  1 22:04:27 Tower kernel: ata5: hard resetting link
Apr  1 22:04:32 Tower kernel: ata5: link is slow to respond, please be patient (ready=0)
Apr  1 22:04:37 Tower kernel: ata5: COMRESET failed (errno=-16)
Apr  1 22:04:37 Tower kernel: ata5: hard resetting link
Apr  1 22:04:42 Tower kernel: ata5: link is slow to respond, please be patient (ready=0)
Apr  1 22:04:47 Tower kernel: ata5: COMRESET failed (errno=-16)
Apr  1 22:04:47 Tower kernel: ata5: hard resetting link
Apr  1 22:04:53 Tower kernel: ata5: link is slow to respond, please be patient (ready=0)
Apr  1 22:05:22 Tower kernel: ata5: COMRESET failed (errno=-16)
Apr  1 22:05:22 Tower kernel: ata5: limiting SATA link speed to 3.0 Gbps
Apr  1 22:05:22 Tower kernel: ata5: hard resetting link
Apr  1 22:05:27 Tower kernel: ata5: COMRESET failed (errno=-16)
Apr  1 22:05:27 Tower kernel: ata5: reset failed, giving up
Apr  1 22:05:27 Tower kernel: ata5.00: disabled
Apr  1 22:05:27 Tower kernel: ata5: EH complete

This is a hardware problem, start by replacing the cables.