Re: freebsd-update install no space left on device

From: Frank Leonhardt <freebsd-doc_at_fjl.co.uk>
Date: Tue, 29 Jul 2025 08:47:32 UTC
On 28/07/2025 02:59, Robert wrote:
> On 7/27/2025 9:16 PM, atsac wrote:
>> Hi,
>>
>> Have you checked 'bectl list’?
>>
>> On a zfs install, updating creates a Boot Environment for the previous
>> install, so the previous version can be booted up on demand. These Boot
>> Environments can build up and consume a fair amount of disk space:
>>
>>    ~> bectl list
>>    BE                                Active Mountpoint Space Created
>>    12.3-RELEASE_2021-12-15_122800    -      -          104M 
>> 2021-12-15 12:28
>>    13.0-RELEASE-p4_2021-12-15_135123 -      -          36.1M 
>> 2021-12-15 13:51
>>    13.1-RELEASE-p3_2022-11-16_135244 -      -          1.36G 
>> 2022-11-16 13:52
>>    13.1-RELEASE-p4_2022-12-13_192926 -      -          3.00G 
>> 2022-12-13 19:29
>>    13.1-RELEASE_2022-11-02_154039    -      -          1.61G 
>> 2022-11-02 15:40
>>    default                           NR     /          48.6G 
>> 2016-06-04 03:16
>>
>> you can remove them with 'bectl destroy':
>>
>>    ~> sudo bectl destroy 13.0-RELEASE-p4_2021-12-15_135123
>>    ~> sudo bectl destroy 13.1-RELEASE-p3_2022-11-16_135244
>>
>> which releases the space consumed by the BE.
>
> I do remember reading about that, thanks for the reminder. My free 
> disk space is a good 65% again now. That clear up the free space 
> issue, and after a reboot, the zroot/ROOT/default size is now 2.9GB, 
> up from 2.0GB but still not the 5.7GB is was yesterday. Is this expected?
>
> -- Robert
>
The mystery to me isn't the free space, it's that the total space has 
changed. I'm watching this in case someone can explain.

You can adjust the available space in a dataset (e.g. zfs get 
quota,refquota zroot/ROOT/default) to stop a dataset consuming the whole 
pool with a rogue logger process (or user) , but you'd know if you'd set 
it yourself.

I don't quite trust df with zfs  - "zfs list" may be more accurate.

zfs list -t all -o name,used,avail,quota,refer,refquota,mountpoint

Regards, Frank.