I am facing a similar issue with free space accounting as described in zpool list vs zfs list - why free space is 10x different?. My situation is however different, even after accounting for the reserved (slop) space, the numbers do not seem to add up.
Zpool list reports 8.1TB free but zfs really only has 339GB free. Slop space was already lowered to 2^-7, since the pool is quite big.
The free space is sorely missed, any help will be highly appreciated. Can the free space be recovered somehow?
#zpool list z
NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
z 65.4T 57.3T 8.10T - - 27% 87% 1.21x ONLINE -
#zfs list z
NAME USED AVAIL REFER MOUNTPOINT
z 69.4T 339G 96K none
#zfs get all z
NAME PROPERTY VALUE SOURCE
z type filesystem -
z creation Mon Jun 8 1:29 2020 -
z used 69.4T -
z available 338G -
z referenced 96K -
z compressratio 1.22x -
z mounted no -
z quota none default
z reservation none default
z recordsize 128K local
z mountpoint none local
z sharenfs off default
z checksum on default
z compression lz4 local
z atime off local
z devices on default
z exec on default
z setuid on default
z readonly off default
z zoned off default
z snapdir hidden default
z aclinherit restricted default
z createtxg 1 -
z canmount on default
z xattr sa local
z copies 1 default
z version 5 -
z utf8only off -
z normalization none -
z casesensitivity sensitive -
z vscan off default
z nbmand off default
z sharesmb off default
z refquota none default
z refreservation none default
z guid 4880913883724291733 -
z primarycache all default
z secondarycache all default
z usedbysnapshots 0B -
z usedbydataset 96K -
z usedbychildren 69.4T -
z usedbyrefreservation 0B -
z logbias latency default
z objsetid 54 -
z dedup on local
z mlslabel none default
z sync disabled local
z dnodesize auto local
z refcompressratio 1.00x -
z written 96K -
z logicalused 83.6T -
z logicalreferenced 42K -
z volmode default default
z filesystem_limit none default
z snapshot_limit none default
z filesystem_count none default
z snapshot_count none default
z snapdev hidden default
z acltype off default
z context none default
z fscontext none default
z defcontext none default
z rootcontext none default
z relatime off default
z redundant_metadata all default
z overlay off default
z encryption off default
z keylocation none default
z keyformat none default
z pbkdf2iters 0 default
z special_small_blocks 64K local
#cat /sys/module/zfs/parameters/spa_slop_shift
7
#zpool iostat -Lv
capacity operations bandwidth
pool alloc free read write read write
------------- ----- ----- ----- ----- ----- -----
z 57.3T 8.10T 317 4.47K 47.0M 29.1M
mirror 13.7T 862G 18 10 11.1M 3.04M
sda - - 9 5 5.53M 1.52M
sdg - - 9 5 5.53M 1.52M
mirror 13.7T 899G 18 10 11.0M 3.03M
sdb - - 9 5 5.51M 1.52M
sdh - - 9 5 5.51M 1.52M
mirror 13.7T 838G 18 10 11.1M 3.04M
sdc - - 9 5 5.54M 1.52M
sdi - - 9 5 5.54M 1.52M
mirror 12.5T 2.04T 17 10 9.87M 3.61M
sdd - - 8 5 4.93M 1.81M
sdj - - 8 5 4.93M 1.81M
dedup - - - - - -
mirror 238G 16.6G 170 4.03K 822K 9.72M
nvme0n1p3 - - 85 2.01K 411K 4.86M
nvme1n1p3 - - 85 2.01K 411K 4.86M
special - - - - - -
mirror 1.76T 1.72T 36 195 1.62M 3.15M
sdf - - 18 97 831K 1.57M
sdl - - 18 97 831K 1.57M
mirror 1.70T 1.78T 37 213 1.58M 3.55M
sde - - 18 106 807K 1.77M
sdk - - 18 106 807K 1.77M
logs - - - - - -
mirror 0 15.5G 0 0 2 0
nvme0n1p2 - - 0 0 1 0
nvme1n1p2 - - 0 0 1 0
cache - - - - - -
nvme0n1p4 569G 37.2G 178 40 2.96M 3.81M
nvme1n1p4 568G 37.8G 178 46 2.96M 3.82M
------------- ----- ----- ----- ----- ----- -----
#
