Re: snapshot space use

[Qu Wenruo <quwenruo@cn.fujitsu.com>]

Hi,

You can use btrfs quota feature to do it.
Like this:

# btrfs quota enable <MNT_POINT>
# btrfs quota rescan -w <MNT_POINT>
# btrfs qgroup show -prce <MNT_POINT>
qgroupid rfer    excl    max_rfer max_excl parent  child
-------- ----    ----    -------- -------- ------  -----
0/5      2248704 12288   0        0        ---     ---
0/256    5509120 3272704 0        0        ---     ---


rfer is all the space the subvolume takes.
excl is the exclusive space the subvolume takes.

You can also refer to 'btrfs-quota'(8) and 'btrfs-qgroup'(8),
Also the following wiki can help:
https://btrfs.wiki.kernel.org/index.php/Quota_support

NOTE: quota is not so stable and has some problem, but should give
you enough info.

Thanks,
Qu

> # zfs list -t snapshot
> NAME                        USED  AVAIL  REFER  MOUNTPOINT
> hetz0/be0-mail@2015-03-10  2.88G      -   387G  -
> hetz0/be0-mail@2015-03-11  1.12G      -   388G  -
> hetz0/be0-mail@2015-03-12  1.11G      -   388G  -
> hetz0/be0-mail@2015-03-13  1.19G      -   388G  -
> hetz0/be0-mail@2015-03-14  1.02G      -   388G  -
> hetz0/be0-mail@2015-03-15   989M      -   386G  -
>
> Is there any way to do something similar to the above ZFS command?  It's handy
> to know which snapshots are taking up the most space, especially when multiple
> subvols are being snapshotted.
>