Unraid 6.7.2  The array refuses to start.   

I am displaying the errors shown from the log.

 

Jul 22 01:39:30 Tower root: starting dockerd ...
Jul 22 01:39:37 Tower root: error: /plugins/preclear.disk/Preclear.php: wrong csrf_token
Jul 22 01:39:38 Tower kernel: BTRFS critical (device loop2): unable to find logical 1125900448038912 length 4096
Jul 22 01:39:38 Tower kernel: BTRFS critical (device loop2): unable to find logical 1125900448038912 length 4096
Jul 22 01:39:38 Tower kernel: BTRFS critical (device loop2): unable to find logical 1125900448038912 length 16384
Jul 22 01:39:38 Tower kernel: BTRFS: error (device loop2) in btrfs_finish_ordered_io:3069: errno=-5 IO failure
Jul 22 01:39:38 Tower kernel: BTRFS info (device loop2): forced readonly
Jul 22 01:39:42 Tower kernel: BTRFS warning (device loop2): btrfs_uuid_scan_kthread failed -30
Jul 22 01:44:37 Tower ntpd[1605]: kernel reports TIME_ERROR: 0x41: Clock Unsynchronized
Jul 22 02:09:27 Tower nginx: 2019/07/22 02:09:27 [error] 7564#7564: *816 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 192.168.1.118, server: , request: "POST /update.htm HTTP/1.1", upstream: "http://unix:/var/run/emhttpd.socket/update.htm", host: "192.168.1.128", referrer: "http://192.168.1.128/Main/Device?name=disk2"
Jul 22 02:09:27 Tower nginx: 2019/07/22 02:09:27 [error] 7564#7564: *809 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 192.168.1.118, server: , request: "POST /update.htm HTTP/1.1", upstream: "http://unix:/var/run/emhttpd.socket/update.htm", host: "192.168.1.128", referrer: "http://192.168.1.128/Main/Device?name=disk2"
Jul 22 02:09:28 Tower nginx: 2019/07/22 02:09:28 [error] 7564#7564: *819 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 192.168.1.118, server: , request: "POST /update.htm HTTP/1.1", upstream: "http://unix:/var/run/emhttpd.socket/update.htm", host: "192.168.1.128", referrer: "http://192.168.1.128/Main/Device?name=disk2"
Jul 22 02:09:28 Tower nginx: 2019/07/22 02:09:28 [error] 7564#7564: *780 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 192.168.1.118, server: , request: "POST /update.htm HTTP/1.1", upstream: "http://unix:/var/run/emhttpd.socket/update.htm", host: "192.168.1.128", referrer: "http://192.168.1.128/Main/Device?name=disk2"
Jul 22 02:09:29 Tower nginx: 2019/07/22 02:09:29 [error] 7564#7564: *845 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 192.168.1.118, server: , request: "POST /update.htm HTTP/1.1", upstream: "http://unix:/var/run/emhttpd.socket/update.htm", host: "192.168.1.128", referrer: "http://192.168.1.128/Main/Device?name=disk2"
Jul 22 02:11:26 Tower nginx: 2019/07/22 02:11:26 [error] 7564#7564: *815 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 192.168.1.118, server: , request: "POST /update.htm HTTP/1.1", upstream: "http://unix:/var/run/emhttpd.socket/update.htm", host: "192.168.1.128", referrer: "http://192.168.1.128/Main/Device?name=disk2"
 

What is the best way to remove a failed disk and replace it?

You should always post the complete diagnostics but based on that your docker image is corrupt, delete and re-create.

Uploading the docker diagnostics

tower-diagnostics-20190722-1358.zip