Hello!
First post here.  Had my system (very small, 6 drives, including cache) for several years, no issues.
All of a sudden I get 'Disk is Write-Protected' error.

 

Diagnostic file attached.
Many thanks for looking into this!
-Miomio

tower-diagnostics-20230217-1250.zip

Edited February 17, 20233 yr by Miomio

Check the connections to the cache drive.  It dropped completely offline

Aye aye aye, 
Thanks for the ultra fast answer!
Problem Solved!   I disconected and reconnected the cables and Voilà!  (still strange as the box is never moved around).
Also strange as yesterday I was seeing the cache drive online (empty files when opening it, which made sense to me).
Thanks again!
-Miomio

Note: In order to learn 'diagnostics', where did you see so fast this was the cache drive?

1 hour ago, Miomio said:

Note: In order to learn 'diagnostics', where did you see so fast this was the cache drive?

Via 2 methods:

 

Method 1:

 

Prior to the drive finally getting kicked out and btrfs having a conniption there is all of this very many times in the syslog

Feb 17 12:47:03 Tower kernel: ata5: hard resetting link
Feb 17 12:47:05 Tower kernel: ata5: SATA link down (SStatus 1 SControl 310)

Searching back in the syslog for ata5 you wind up with

Feb 17 12:43:36 Tower kernel: ata5: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
Feb 17 12:43:36 Tower kernel: ata5.00: ATA-10: WDC WD10SPZX-21Z10T0,      WD-WX61A7852UTZ, 02.01A02, max UDMA/133

Cross reference that drive  in the SMART section of the diagnostics and it doesn't exist at all (ie: no drive is connected)

 

But it was connected originally as the cache drive

Feb 17 12:43:39 Tower emhttpd: import 30 cache device: (sdb) WDC_WD10SPZX-21Z10T0_WD-WX61A7852UTZ

 

Which leads to

1 hour ago, Squid said:

Check the connections to the cache drive.  It dropped completely offline

 

 

But, personally I think it was mostly method #2: