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

On 9/24/25 01:37, Andrea Venturoli wrote:
> On 9/23/25 16:14, Andrea Venturoli wrote:
>> On 9/21/25 23:21, David Christensen wrote:
>>
>>> Have you done a scrub recently?
>>
>> The pool was last scubbed by periodic a month ago.
>> I've launched a new scrub manually now, but I guess it won't do much, 
>> given the problem arised long ago.
> 
> As expected, scrub recovered no space.
> 
>> I already deleted those snapshots, remember?
>>
>> I wonder if deleting all the others would solve...
> 
> Deleting *all* snapshots didn't help either.
> 
>   bye
>      av.


I think you have found a ZFS bug, or at least a misfeature.  Filing a 
bug report seems appropriate, but I am uncertain how to furnish the 
oversize send stream file.  (USB flash drive and postal mail?)


As for fixing your server, that leaves your rsync(1) idea, my backup/ 
wipe/ install/ restore idea, or some combination of the two.


If there is a backup/ restore solution for ezjail, use it.


I foresee a non-trivial amount of work to do before reaching rsync(1) -- 
MBR's, partition schemes, FreeBSD slices (BIOS), FreeBSD bootloader 
partitions, EFI system partitions and gmirror and contents (UEFI), swap 
partitions and gmirror, ZFS partitions and zpool mirror, ZFS filesystem 
hierarchy and properties, etc..  Building all of that from the bottom up 
is either a lot of manual install work or rewriting the much of the 
FreeBSD installer.  If you are clever, perhaps dd(1) and other surgery. 
I would be inclined to let the FreeBSD installer do most of the work 
(with manual partitioning) and then modify the result as required.


I have never used rsync(1) to copy an OS filesystem; I use dd(1).  Once 
the ZFS filesystem hierarchy is ready, are you confident that rsync(1) 
can correctly copy every entry (data plus metadata) in every old 
filesystem into the empty new filesystems; such that the old disks can 
be removed, the copied OS on the new disk disks will boot, all of the 
copied jails will start, all the copied data and metadata will be 
correct, and everything will work?  I have more confidence in letting 
the FreeBSD installer build a complete and working OS, adding jails, 
installing and configuring software, and restoring data.


Do you have a networked version control system?  I used CVS for system 
and service configuration files, scripts, administrator notes, and other 
useful files; it is invaluable.


David