Differences in reporting by du df and usedbydataset
Jason Breitman
jbreitman at zxcvm.com
Tue Apr 15 12:31:24 UTC 2014
I have not received a reply to my question and wanted to post again so that the group could see the question again.
Jason Breitman
jbreitman at zxcvm.com
On Mar 26, 2014, at 12:53 PM, Jason Breitman <jbreitman at zxcvm.com> wrote:
The different disk usage measurements are frequently discussed and most of the time snapshots are the source of confusion.
I use refquota to avoid this confusion for user based file systems, but can not explain the below reports and hope you can help.
Why is there an ~18 GB difference between du and df / usedbydataset?
I included additional information so that you can see that used = usedbysnapshots + usedbydataset and that there are no reservations.
# du -sh /tank/users/auser
5.1G /tank/users/auser
# df -h /tank/users/auser
Filesystem Size Used Avail Capacity Mounted on
tank/users/auser 35G 23G 11G 66% /tank/users/auser
# zfs get usedbydataset tank/users/auser
NAME PROPERTY VALUE SOURCE
tank/users/auser usedbydataset 23.2G -
# zfs get used,usedbysnapshots,usedbydataset tank/users/auser
NAME PROPERTY VALUE SOURCE
tank/users/auser used 63.9G -
tank/users/auser usedbysnapshots 40.7G -
tank/users/auser usedbydataset 23.2G -
# zfs get refreservation,usedbyrefreservation tank/users/auser
NAME PROPERTY VALUE SOURCE
tank/users/auser refreservation none default
tank/users/auser usedbyrefreservation 0
OS: Freebsd 9.1
# zpool upgrade -v
This system is currently running ZFS pool version 28.
The following versions are supported:
VER DESCRIPTION
--- --------------------------------------------------------
1 Initial ZFS version
2 Ditto blocks (replicated metadata)
3 Hot spares and double parity RAID-Z
4 zpool history
5 Compression using the gzip algorithm
6 bootfs pool property
7 Separate intent log devices
8 Delegated administration
9 refquota and refreservation properties
10 Cache devices
11 Improved scrub performance
12 Snapshot properties
13 snapused property
14 passthrough-x aclinherit
15 user/group space accounting
16 stmf property support
17 Triple-parity RAID-Z
18 Snapshot user holds
19 Log device removal
20 Compression using zle (zero-length encoding)
21 Deduplication
22 Received properties
23 Slim ZIL
24 System attributes
25 Improved scrub stats
26 Improved snapshot deletion performance
27 Improved snapshot creation performance
28 Multiple vdev replacements
For more information on a particular version, including supported releases,
see the ZFS Administration Guide.
# zfs upgrade -v
The following filesystem versions are supported:
VER DESCRIPTION
--- --------------------------------------------------------
1 Initial ZFS filesystem version
2 Enhanced directory entries
3 Case insensitive and filesystem user identifier (FUID)
4 userquota, groupquota properties
5 System attributes
For more information on a particular version, including supported releases,
see the ZFS Administration Guide.
Jason Breitman
jbreitman at zxcvm.com
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