Filesystem deduplication (was:solution to / full)
On 3/2/23 15:16, songbird wrote:
i could find a lot of space by deduping backups and pictures
but that is on my TODO list for the year 2026 at the rate i'm
going. it may end up being much more time efficient to just
go out and buy another 2TB SSD and swap that for my smaller
one and call it good enough.
Block-level compression and deduplication are killer features of ZFS,
and backup storage is the canonical use-case.
The most recent backup of my daily driver is 4.9G:
2023-03-03 10:16:10 toor@f1 ~
# du -hsx /altroot/p1/var/local/backup/laalaa.tracy.holgerdanske.com
4.9G /altroot/p1/var/local/backup/laalaa.tracy.holgerdanske.com
I have 258 previous backups:
2023-03-03 10:15:03 toor@f1 ~
# ls
/altroot/p1/var/local/backup/laalaa.tracy.holgerdanske.com/.zfs/snapshot
| wc -l
258
The apparent size of the previous backups is 1.2T:
2023-03-03 10:15:55 toor@f1 ~
# du -hs
/altroot/p1/var/local/backup/laalaa.tracy.holgerdanske.com/.zfs/snapshot
1.2T
/altroot/p1/var/local/backup/laalaa.tracy.holgerdanske.com/.zfs/snapshot
Actual disk usage is 29.0G:
2023-03-03 10:50:00 toor@f1 ~
# zfs get
compression,compressratio,dedup,used,usedbydataset,usedbysnapshots
p1/backup/laalaa.tracy.holgerdanske.com | sort
NAME PROPERTY VALUE
SOURCE
p1/backup/laalaa.tracy.holgerdanske.com compression lz4
inherited from p1
p1/backup/laalaa.tracy.holgerdanske.com compressratio 2.10x -
p1/backup/laalaa.tracy.holgerdanske.com dedup verify
inherited from p1/backup
p1/backup/laalaa.tracy.holgerdanske.com used 29.0G -
p1/backup/laalaa.tracy.holgerdanske.com usedbydataset 4.89G -
p1/backup/laalaa.tracy.holgerdanske.com usedbysnapshots 24.1G -
David
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