hammer PFSes destroy does not give back full space allocated to PFS

[Siju George <sgeorge.ml2@xxxxxxxxx>]

Hi,


I was mirroring PFSes from 3.1 dev to slaves in 3.02 and I found that
the PFSes took more space on the 3.02 slave.
Investigating I found this strange thing


94 GB is allocated for this slave PFS. But when it is removed only 52
GB is freed :-(

Any Idea why this is?

dfly-bkpsrv2# hammer dedup /pfs/software
Dedup running
Dedup /pfs/software succeeded
Dedup ratio = 1.06
      100 GB referenced
       94 GB allocated
     4339 KB skipped
         429 CRC collisions
           0 SHA collisions
           1 bigblock underflows
           0 new dedup records
           0 new dedup bytes


dfly-bkpsrv2# df -h
Filesystem               Size   Used  Avail Capacity  Mounted on
ROOT                     459G   354G   106G    77%    /
devfs                    1.0K   1.0K     0B   100%    /dev
/dev/serno/QM00001.s1a   756M   168M   527M    24%    /boot
/pfs/@@-1:00001          459G   354G   106G    77%    /var
/pfs/@@-1:00002          459G   354G   106G    77%    /tmp
/pfs/@@-1:00003          459G   354G   106G    77%    /usr
/pfs/@@-1:00004          459G   354G   106G    77%    /home
/pfs/@@-1:00005          459G   354G   106G    77%    /usr/obj
/pfs/@@-1:00006          459G   354G   106G    77%    /var/crash
/pfs/@@-1:00007          459G   354G   106G    77%    /var/tmp
procfs                   4.0K   4.0K     0B   100%    /proc
dfly-bkpsrv2# ls
home            software        usr             var
var.tmp         vms2-lxc
mysql-baks      tmp             usr.obj         var.crash       vms1-lxc
dfly-bkpsrv2# hammer pfs-destroy /pfs/software
You have requested that PFS#11 () be destroyed
This will irrevocably destroy all data on this PFS!!!!!
Do you really want to do this? y
Destroying PFS #11 () in  5 4 3 2 1.. starting destruction pass
pfs-destroy of PFS#11 succeeded!
dfly-bkpsrv2# df -h
Filesystem               Size   Used  Avail Capacity  Mounted on
ROOT                     459G   302G   158G    66%    /
devfs                    1.0K   1.0K     0B   100%    /dev
/dev/serno/QM00001.s1a   756M   168M   527M    24%    /boot
/pfs/@@-1:00001          459G   302G   158G    66%    /var
/pfs/@@-1:00002          459G   302G   158G    66%    /tmp
/pfs/@@-1:00003          459G   302G   158G    66%    /usr
/pfs/@@-1:00004          459G   302G   158G    66%    /home
/pfs/@@-1:00005          459G   302G   158G    66%    /usr/obj
/pfs/@@-1:00006          459G   302G   158G    66%    /var/crash
/pfs/@@-1:00007          459G   302G   158G    66%    /var/tmp
procfs                   4.0K   4.0K     0B   100%    /proc


Thanks

Siju