Wow, thank you so much for your detailed replies!
It would be great if your explanations were included in the wiki.
My backup script uses snapshot + rsync but I've just realized that a lot of
data was duplicated (my script must have skipped the snapshotting part somehow).
I've used "bedup" to deduplicate the data and it has saved more than 250 GB of
duplicated data.
Vianney
On 15/06/2017 11:44, Vianney Stroebel wrote:
On a backup drive for a home computer, disk usage as shown by 'btrfs fi show'
is more than double the snapshots exclusive data as shown by "btrfs qgroup
show" (574 GB vs 265 GB).
I've done a lot of research online and I couldn't find any answer to this
problem.
Output of some commands:
uname -a
Linux viybel-pc 4.10.0-22-generic #24-Ubuntu SMP Mon May 22 17:43:20 UTC 2017
x86_64 x86_64 x86_64 GNU/Linux
btrfs --version
btrfs-progs v4.9.1
sudo btrfs fi show
Label: 'btrfs-backup' uuid: 35905dc5-1400-4687-8be7-cf87d6ad0980
Total devices 1 FS bytes used 573.89GiB
devid 1 size 698.64GiB used 697.04GiB path /dev/sdb1
btrfs fi df /mnt/btrfs-backup
Data, single: total=670.01GiB, used=564.26GiB
System, DUP: total=8.00MiB, used=112.00KiB
System, single: total=4.00MiB, used=0.00B
Metadata, DUP: total=13.50GiB, used=8.64GiB
Metadata, single: total=8.00MiB, used=0.00B
GlobalReserve, single: total=512.00MiB, used=14.95MiB
From https://github.com/agronick/btrfs-size (i.e. more readable "btrfs qgroup
show")
btrfs-size /mnt/btrfs-backup
==================================================================================================================================
Snapshot / Subvolume ID Total
Exclusive Data
==================================================================================================================================
10726 gen 216807 top level 5 path full/2016-06-19_12-32-01 10726
208.68GB 208.68GB
21512 gen 216853 top level 5 path full/2016-12-14_16-21-34 21512
166.98GB 40.36GB
23054 gen 216853 top level 5 path full/2017-03-03_08-47-00 23054
154.79GB 7.53GB
25451 gen 216856 top level 5 path full/2017-04-14_21-54-25 25451
123.48GB 3.07GB
26514 gen 216862 top level 5 path full/2017-05-02_14-58-09 26514
123.70GB 5.03GB
28499 gen 218095 top level 5 path full/2017-06-11_19-29-16 28499
154.65GB 169.78MB
28556 gen 218094 top level 5 path full/2017-06-13_03-15-00 28556
154.88GB 403.89MB
==================================================================================================================================
Exclusive
Total: 265.23GB
Feel free to ask me any question.
Vianney
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