I am noticing a lot of Btrfs errors going on from one of my cache drives. Is this a failure of the drive? I attached my diagnostics. 

vengeance-diagnostics-20181114-1123.zip

Nov 11 22:27:00 Vengeance kernel: BTRFS info (device sdg1): bdev /dev/sdg1 errs: wr 24652993, rd 16582576, flush 1218175, corrupt 0, gen 0

Lots of errors on one of the cache devices, these are read/write errors, i.e. hardware problem.

 

Likely because of those filesystem has issues, run a scrub and check that there are no uncorrected errors, but note that data in any NOCOW shares can't be checked/fixed.

Didn't' check the complete syslog, more errors now on another cache device:

 

Nov 12 11:20:38 Vengeance kernel: BTRFS error (device sdb1): bdev /dev/sdh1 errs: wr 394525, rd 74047, flush 13805, corrupt 0, gen 0

Replace cables, if errors persist it can be the devices.

Thank you for the reply I will run a scrub and see what comes up. I also wanted to ask what could be sdh1. I only have 7 devices which includes the flash drive. 

Cache pool is indicating there's a missing device:

 

Nov 11 22:27:00 Vengeance emhttpd: cache TotDevices: 4
Nov 11 22:27:00 Vengeance emhttpd: cache NumDevices: 3
Nov 11 22:27:00 Vengeance emhttpd: cache NumFound: 3
Nov 11 22:27:00 Vengeance emhttpd: cache NumMissing: 1
Nov 11 22:27:00 Vengeance emhttpd: cache NumMisplaced: 0
Nov 11 22:27:00 Vengeance emhttpd: cache NumExtra: 0
Nov 11 22:27:00 Vengeance emhttpd: cache LuksState: 0

Likely one of them dropped offline then came back up with a different identifier, this can confuse btrfs, most commonly with SSD these issues are cable related.

The scrub looks like it came back fine, no uncorrected errors. I'll replace cables and post an update once that is done. Thank you for your help.