External Drive present in /Volumes but not diskutil

[sanderr2]

So one of my external hard drives named "Backup" has started "disappearing" - I noticed Carbon Copy Cloner failing. The Drive/Volume doesn't show up in diskutil list in terminal (or Finder or Disk Utility) but in terminal I can navigate to the volume and it's subdirectories in /Volumes which seems very odd.

If I use df on the /Volumes/Backup (see output below) it seems to show that the volume is mapped to another disk on a "synthesised" volume /Systems/Volumes/Data - "Data" isn't a Volume that appears in /Volumes.

Strange? or am I missing something?!

Thanks!
Rob



df /Volumes/Backup

Filesystem 512-blocks Used Available Capacity iused ifree %iused Mounted on

/dev/disk2s1 2189683984 916351552 1225460728 43% 1433065 10946986855 0% /System/Volumes/Data

CETs-iMac:~ rob$ diskutil list

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *121.3 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_APFS Container disk2 121.1 GB disk0s2



/dev/disk1 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_APFS Container disk2 1000.0 GB disk1s2



/dev/disk2 (synthesized):

#: TYPE NAME SIZE IDENTIFIER

0: APFS Container Scheme - +1.1 TB disk2

Physical Stores disk1s2, disk0s2

1: APFS Volume Macintosh HD - Data 469.2 GB disk2s1

2: APFS Volume Preboot 81.6 MB disk2s2

3: APFS Volume Recovery 528.9 MB disk2s3

4: APFS Volume VM 4.3 GB disk2s4

5: APFS Volume Macintosh HD 10.7 GB disk2s5



/dev/disk3 (external, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *4.0 TB disk3

1: EFI EFI 209.7 MB disk3s1

2: Apple_HFS Media Library 4.0 TB disk3s2

 

[Fishrrman]

How old is the drive?
If it's older, could it be failing mechanically?

Is the drive used ONLY for CCC cloned backups?

If so, what I would try:
1. Use disk utility to ERASE the drive -- yes, erase it
2. Use disk utility's "repair disk" function on the drive.
3. Does it give a good report, or find problems?
4. If it gives "a good report", I'd REPEAT the "repair disk" function 5 times in a row.
5. If I got a good report EVERY time, I'd "start over" with CCC.

Since CCC is "a copy" of the internal, you don't really lose anything by erasing the cloned backup and starting over. Only exception would be if you use the "safety net" feature (I don't use it).