sudo: unable to write to /var/lib/sudo/ts/admin: No space left on device

Let me just say that I am extremely appreciative and grateful for the time, thought and engagment that anyone offers on a thread like mine, even if my choices and actions may be a source of frustration to those with vastly more experience in using the CLI and delving deep into OSes.

Know that my use of LLMs like DeepSeek, ChatGPT etc, is, in the main, to ask basic questions about commands that do simple things to avoid clogging up a thread like this and exhausting the patience of those for whom it is second nature, whether be it because it's their job or a long-time computer hobbyist & tinkerer. I am mindful that the informal chatty nature of these LLMs whilst seductive, can offer poor or just plain incorrect 'advice' for the more complicated questions and ideally, s/b run by anyone who is willing and able to read over it in forums like this.

StephenB wrote:

This is normal - did you remove files to bring it down to this level?

Yes. I installed ncdu and found that Syncthing (installed incorrectly in this location to begin with) was taking up 2+GB space, so deleted it all as I'll install it again in a different partition, setup and run an initial sync again, no big deal apart from the time a first sync takes.

Before that, I deleted everything from /var/lib/squeezeboxserver/cache, which was recommended on a help thread I started within the Lyrion (renamed from Logitech) support forums but that only reclaimed a few hundred MBs.

StephenB wrote:

Instead run this (using ssh on the NAS, logged in as root) :

Thanks for the suggestion. I ran it, despite the ominous warning about how long it may take, it took less than a minute, no error messages and the output was:

WARNING:

	Full balance without filters requested. This operation is very
	intense and takes potentially very long. It is recommended to
	use the balance filters to narrow down the scope of balance.
	Use 'btrfs balance start --full-balance' option to skip this
	warning. The operation will start in 10 seconds.
	Use Ctrl-C to stop it.
10 9 8 7 6 5 4 3 2 1
Starting balance without any filters.
Done, had to relocate 11 out of 11 chunks

StephenB wrote:

Which is what I see on bothe new discussions and replies. What format options are you looking for????

I just had more options for the initial post that started this thread and expected to be offered the same options for any subsequent post.

I think I was mainly after the Preformatted option as part of the Paragraph dropdown but you don't this for subsequent replies. Anyway, a minor issue that can be worked around, a little jarring but no biggie.

Sandshark wrote:

If the files are corrupted, then a BTRFS repair isn't going to fix them, but an OS re-install might. But your OS partition is far too full to try that now.

OK, I have taken the advice of StephenB​ on board and as I mentioned at the top of this post, have deleted a bunch of files from the LMS cache sub-folder and deleted Syncthing entirely as I shouldn't have installed it on the root partition in the first place (and ignored the nagging warning messages that would pop up sometimes when I logged into the Syncthing GUI, yup my bad).

At time of writing, running df -h gives:

/dev/md0        4.0G  1.4G  2.5G  35% /

Sandshark wrote:

You need to run btrfs filesystem df /.

OK, that gives:

Data, single: total=1.62GiB, used=1.25GiB
System, DUP: total=32.00MiB, used=16.00KiB
Metadata, DUP: total=128.00MiB, used=20.59MiB
GlobalReserve, single: total=16.00MiB, used=0.00B

Are you able to say if that looks ok? Hopefully it does.

I've slightly messed up my LMS, so I'm going to head over to the thread I've posted there because although the LMS rescanned my music library, all the meta data associated with the files disappeared, probably with the deletion of the contents of the cache directory but I'm hoping that the data I need is still within the files in the prefs directory.

I think I need to move the LMS installation from the OS partition too and that could tie in with installing a new stable version of the software that has recently been released (9.0.2) so I could install the LMS correctly in a different location and 🤞 restore all the missing meta data and ratings, assuming I still have the necessary files.

Do you recommend any further actions?

Appreciate your time and replies.