Re: [List] Cannot find out what uses space in ZFS dataset

From: <freebsd_at_vanderzwan.org>
Date: Thu, 18 Sep 2025 16:44:17 UTC

> On 18 Sep 2025, at 17:57, Andrea Venturoli <ml@netfence.it> wrote:
> 
>> zfs list -t all -o name,refer,used,usedbychildren,usedbydataset,usedbyrefreservation,usedbysnapshots
> 
> I don't think I'm interested in snapshots, but in any case:
>> # zfs list -t all -o name,refer,used,usedbychildren,usedbydataset,usedbyrefreservation,usedbysnapshots|grep default
>> zroot/ROOT/default                                      62.1G  70.9G         0B   62.1G             0B     8.76G
>> zroot/ROOT/default@auto_zroot-20241014020000            3.11G  2.95G          -       -              -         -
>> zroot/ROOT/default@auto_zroot-20241113010000            3.01G   198M          -       -              -         -
>> zroot/ROOT/default@auto_zroot-20241213010000            3.30G  70.7M          -       -              -         -
>> zroot/ROOT/default@auto_zroot-20250112010000            3.30G  60.4M          -       -              -         -
>> zroot/ROOT/default@auto_zroot-20250211010000            3.30G  64.9M          -       -              -         -
>> zroot/ROOT/default@auto_zroot-20250313010000            3.31G   263M          -       -              -         -
>> zroot/ROOT/default@auto_zroot-20250412020000            3.32G   149M          -       -              -         -
>> zroot/ROOT/default@auto_zroot-20250512020000            3.32G  68.6M          -       -              -         -
>> zroot/ROOT/default@auto_zroot-20250611020000            3.34G   209M          -       -              -         -
>> zroot/ROOT/default@auto_zroot-20250711020000            62.2G   407M          -       -              -         -

Here the refer jumps from 3.34 to 62.2 GB, so it looks like your missing data is in this snapshot.

I guess  'zfs diff zroot/ROOT/default@auto_zroot-20250611020000  zroot/ROOT/default@auto_zroot-20250711020000'  can show what happened.

>> zroot/ROOT/default@auto_zroot-20250810020000            62.1G   107M          -       -              -         -
>> zroot/ROOT/default@auto_zroot-20250821020000            62.1G  36.2M          -       -              -         -
>> zroot/ROOT/default@auto_zroot-20250828020000            62.1G  33.9M          -       -              -         -


Cheers,
	Paul