Re: [List] Cannot find out what uses space in ZFS dataset
Date: Thu, 18 Sep 2025 19:50:28 UTC
> On 18 Sep 2025, at 20:41, Andrea Venturoli <ml@netfence.it> wrote: > > On 9/18/25 20:00, freebsd@vanderzwan.org wrote: > >>> In any case, I tried deleting the 20250711020000 snapshot. >>> Now the jump in refer just moved to the next:> zfs list -t all -o name,refer,used,usedbychildren,usedbydataset,usedbyrefreservation,usedbysnapshots|grep default >>>> zroot/ROOT/default 62.1G 70.5G 0B 62.1G 0B 8.36G >>>> ... >>>> zroot/ROOT/default@auto_zroot-20250611020000 3.34G 215M - - - - >>>> zroot/ROOT/default@auto_zroot-20250810020000 62.1G 116M - - - - >>>> ... >>> Still "zfs send" generates the same huge amount of data. >>> >>> >> That’s because for some reason the data is still referenced in snapshots. > > Then is usedbysnapshot lying??? > > > >> If you delete all snapshots up to and including 20250810020000 you should see that usage drop to what you expect. > > Unfortunately not. My bad, I had to leave my desk and before I got back I realized myself I was wrong. > >> # zfs list -t snap|grep default >> zroot/ROOT/default@auto_zroot-20250821020000 41.0M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250828020000 33.9M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250904020000 28.1M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250909020000 10.1M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250911020000 10.3M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250912020000 1.84M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250913020000 5.97M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250914020000 5.79M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250915020000 4.75M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250916020000 2.48M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250917020000 2.09M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250917210000 1.21M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250917220000 1.54M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250917230000 1.36M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918000000 1.44M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918010000 1.42M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918020000 1.65M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918030000 1.95M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918040000 964K - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918050000 1.61M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918060000 960K - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918070000 1.48M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918080000 1.47M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918090000 1.74M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918100000 2.07M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918110000 2.03M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918120000 892K - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918130000 1.19M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918140000 1.62M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918150000 1.81M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918160000 1.58M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918170000 1.88M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918180000 1.99M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918190000 1.12M - 62.1G - >> zroot/ROOT/default@auto_zroot-20250918200000 972K - 62.1G - >> # zfs list -o name,refer,used,usedbysnapshots|grep default >> zroot/ROOT/default 62.1G 62.4G 263M > > > > > >> One more thing, can you show the output of ’zfs list -o space |grep zroot’ to list all datasets in the pool ? > >> # zfs list -o space |grep zroot >> zroot 1.95T 1.50T 536K 88K 0B 1.50T >> zroot/ROOT 1.95T 62.4G 0B 88K 0B 62.4G >> zroot/ROOT/default 1.95T 62.4G 263M 62.1G 0B 0B >> zroot/ezjail 1.95T 1.40T 328K 128K 0B 1.40T >> zroot/ezjail/backup 1.95T 33.9G 9.00G 1.29G 0B 23.7G >> zroot/ezjail/backup/cache 1.95T 1.38G 1.20G 182M 0B 0B >> zroot/ezjail/backup/postgres 1.95T 22.3G 17.7G 4.55G 0B 0B >> zroot/ezjail/backup/tmp 1.95T 128K 0B 128K 0B 0B >> zroot/ezjail/basejail 1.95T 6.82G 5.52G 1.31G 0B 0B >> zroot/ezjail/dc 1.95T 4.52G 2.59G 793M 0B 1.16G >> zroot/ezjail/dc/cache 1.95T 1.16G 1.04G 119M 0B 0B >> zroot/ezjail/dc/tmp 1.95T 128K 0B 128K 0B 0B >> zroot/ezjail/fs 1.95T 1.21T 5.73G 28.8M 0B 1.21T >> zroot/ezjail/fs/cache 1.95T 498M 462M 36.3M 0B 0B >> zroot/ezjail/fs/images 1.95T 118G 0B 118G 0B 0B >> zroot/ezjail/fs/log 1.95T 89.3G 56.6G 32.7G 0B 0B >> zroot/ezjail/fs/shares 1.95T 481G 59.1G 422G 0B 0B >> zroot/ezjail/fs/tmp 1.95T 144K 0B 144K 0B 0B >> zroot/ezjail/fs/usr 1.95T 547G 1.18G 305M 0B 546G >> zroot/ezjail/fs/usr/home 1.95T 546G 31.9G 514G 0B 0B >> zroot/ezjail/ids 1.95T 16.2G 2.55G 584M 0B 13.1G >> zroot/ezjail/ids/cache 1.95T 96.5M 0B 96.5M 0B 0B >> zroot/ezjail/ids/logs 1.95T 12.6G 0B 12.6G 0B 0B >> zroot/ezjail/ids/spool 1.95T 364M 0B 364M 0B 0B >> zroot/ezjail/ids/tmp 1.95T 128K 0B 128K 0B 0B >> zroot/ezjail/mail 1.95T 128G 3.31G 662M 0B 124G >> zroot/ezjail/mail/cache 1.95T 558M 449M 110M 0B 0B >> zroot/ezjail/mail/clamav 1.95T 414M 0B 414M 0B 0B >> zroot/ezjail/mail/imap 1.95T 123G 17.2G 106G 0B 0B >> zroot/ezjail/mail/tmp 1.95T 344K 0B 344K 0B 0B >> zroot/ezjail/newjail 1.95T 70.8M 16K 70.8M 0B 0B >> zroot/ezjail/proxy 1.95T 6.32G 737M 222M 0B 5.39G >> zroot/ezjail/proxy/tmp 1.95T 152K 0B 152K 0B 0B >> zroot/ezjail/proxy/var 1.95T 5.39G 122M 22.5M 0B 5.24G >> zroot/ezjail/proxy/var/cache 1.95T 328M 294M 33.1M 0B 0B >> zroot/ezjail/proxy/var/clamav 1.95T 414M 0B 414M 0B 0B >> zroot/ezjail/proxy/var/log 1.95T 3.55G 2.54G 1.02G 0B 0B >> zroot/ezjail/proxy/var/squid 1.95T 989M 0B 989M 0B 0B >> zroot/home 1.95T 22.6G 22.6G 18.8M 0B 0B >> zroot/tmp 1.95T 134M 0B 134M 0B 0B >> zroot/usr 1.95T 11.8G 0B 88K 0B 11.8G >> zroot/usr/obj 1.95T 7.84G 0B 7.84G 0B 0B >> zroot/usr/src 1.95T 3.93G 0B 3.93G 0B 0B >> zroot/var 1.95T 5.32G 0B 88K 0B 5.32G >> zroot/var/audit 1.95T 88K 0B 88K 0B 0B >> zroot/var/cache 1.95T 213M 0B 213M 0B 0B >> zroot/var/clamav 1.95T 425M 0B 425M 0B 0B >> zroot/var/crash 1.95T 88K 0B 88K 0B 0B >> zroot/var/dumps 1.95T 88K 0B 88K 0B 0B >> zroot/var/log 1.95T 4.69G 3.74G 978M 0B 0B >> zroot/var/mail 1.95T 640K 528K 112K 0B 0B >> zroot/var/tmp 1.95T 88K 0B 88K 0B 0B > > > >> And the output of ‘zpool list’. > >> # zpool list >> NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT >> vm 446G 361G 85.4G - - 54% 80% 1.00x ONLINE - >> zroot 3.56T 1.50T 2.06T - - 19% 42% 1.00x ONLINE - > > Those look pretty normal. One thing that could explain this difference between du and zfs used is if you mount a small/empty filesystem on top of a very large directory. In that case the content of the directory would be invisible because the mount masks it. Does the output of the mount command show any strange mounts that could cause this ? About the du output what does ‘du -mx / |sort -n |tail ‘ show ? Cheers, Paul > > > bye & Thanks > av. >