Копипаста

ressurected# dd if=/dev/zero of=test.img bs=1m count=15000
15000+0 records in
15000+0 records out
15728640000 bytes transferred in 299.641029 secs (52491610 bytes/sec)
ressurected# vnconfig -c vn test.img
vn4
ressurected# disklabel64 -w -r /dev/vn4s0 auto
ressurected# disklabel64 -e /dev/vn4s0
ressurected# newfs_hammer -f -L TEST /dev/vn4s0a
Volume 0 DEVICE /dev/vn4s0a     size  14.65GB
initialize freemap volume 0
initializing the undo map (504 MB)
---------------------------------------------
1 volume total size  14.65GB version 6
boot-area-size:       32.00MB
memory-log-size:      32.00MB
undo-buffer-size:    504.00MB
total-pre-allocated:   0.51GB
fsid:                44b3c7ea-9f56-11e5-a636-11feed02b918

NOTE: Please remember that you may have to manually set up a
cron(8) job to prune and reblock the filesystem regularly.
By default, the system automatically runs 'hammer cleanup'
on a nightly basis.  The periodic.conf(5) variable
'daily_clean_hammer_enable' can be unset to disable this.
Also see 'man hammer' and 'man HAMMER' for more information.

WARNING: HAMMER filesystems less than 50GB are not recommended!
You may have to run 'hammer prune-everything' and 'hammer reblock'
quite often, even if using a nohistory mount.
ressurected# mount /dev/vn4s0a /mnt/
ressurected# cd /mnt/
ressurected# touch it
ressurected# hammer snapq .
./@@0x0000000100008020
ressurected# touch seems
ressurected# hammer snapq .
./@@0x0000000100008080
ressurected# touch to\ be\ working
ressurected# hammer snapq .
./@@0x0000000100008120
ressurected# cd
ressurected# umount /mnt/
ressurected# mount /dev/vn4s0a /mnt/
ressurected# cd /mnt/
ressurected# hammer snapq .
./@@0x0000000000000000
ressurected# touch no\ it\ does\ not
ressurected# hammer snapq .
./@@0x0000000100010220
ressurected# hammer snapls .
Snapshots on .  PFS #0
Transaction ID          Timestamp               Note
0x0000000000000000      2015-12-10 19:17:09 MSK -
0x0000000100008020      2015-12-10 19:16:29 MSK -
0x0000000100008080      2015-12-10 19:16:35 MSK -
0x0000000100008120      2015-12-10 19:16:54 MSK -
0x0000000100010220      2015-12-10 19:17:23 MSK -