I often mount a drive in a Star Tech external caddy via esata as an unassigned disk.  When it drops off line (without being unmounted, usually happens a few hours after mounting) the following error message is flooding the system log:

 

Sep 18 10:31:01 Tower kernel: BTRFS error (device dm-0): bdev /dev/mapper/Unassigned_Disk_VM errs: wr 0, rd 8019, flush 0, corrupt 0, gen 0

 

I have enabled esata in the motherboard bios for this sata connection.  Any suggestions? Diagnostics attached.

tower-diagnostics-20200918-1033.zip

Edited September 18, 20205 yr by Woodpusherghd

Try a different cable, and one as short as possible, initial connection, at least the ones I saw are only linking at 1.5gbps:

 

Sep 12 10:59:21 Tower kernel: ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 310)

 

That already suggests a connection quality problem, later the disk dropped offline:

 

Sep 15 07:14:24 Tower kernel: ata1: hard resetting link
Sep 15 07:14:24 Tower kernel: ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
Sep 15 07:14:54 Tower kernel: ata1.00: qc timeout (cmd 0xec)
Sep 15 07:14:54 Tower kernel: ata1.00: failed to IDENTIFY (I/O error, err_mask=0x4)
Sep 15 07:14:54 Tower kernel: ata1.00: revalidation failed (errno=-5)
Sep 15 07:14:54 Tower kernel: ata1.00: disabled