btrfs filesystem resize "no enough free space"

I use two identical 1TB disks with btrfs, non raid atm. I have used a few 100 GB in the past and now copy large files to it and so I started to check how it works and if everything is okay; But it seems somehow I need to allocate more space and cannot figure out how.

root@k17:~# btrfs filesystem df /media/konnertz/1abdc5b6-d22e-45f4-93b1-b52bfbc01ee4/
Data, single: total=794.01GiB, used=786.99GiB
System, single: total=4.00MiB, used=96.00KiB
Metadata, single: total=17.01GiB, used=1.05GiB
GlobalReserve, single: total=360.00MiB, used=0.00B


root@k17:~# btrfs filesystem show 
Label: none  uuid: 1abdc5b6-d22e-45f4-93b1-b52bfbc01ee4
    Total devices 2 FS bytes used 787.79GiB
    devid    1 size 931.51GiB used 405.02GiB path /dev/sde
    devid    2 size 931.51GiB used 406.00GiB path /dev/sdd

I tried resizing

root@k17:~# btrfs fi resize +50g /media/konnertz/1abdc5b6-d22e-45f4-93b1-b52bfbc01ee4/ 
Resize '/media/konnertz/1abdc5b6-d22e-45f4-93b1-b52bfbc01ee4/' of '+50g'    
ERROR: unable to resize '/media/konnertz/1abdc5b6-d22e-45f4-93b1-b52bfbc01ee4/': no enough free space

How is it supposed to work? (it is non-root filesystem)

UPDATE It seems it's automatically done... cool. I just kept copying data and now it shows 808G total which was 791G before

root@k17:~# btrfs filesystem df /media/konnertz/1abdc5b6-d22e-45f4-93b1-b52bfbc01ee4/
Data, single: total=808.01GiB, used=800.28GiB
System, single: total=4.00MiB, used=96.00KiB
Metadata, single: total=17.01GiB, used=1.07GiB
GlobalReserve, single: total=368.00MiB, used=36.00KiB

btrfs

groovehunter

Posted 2017-06-13T06:42:05.440

Reputation: 326

Are you sure the disks are 2TB each? The value of 931.51GiB translates to (almost exactly) 1TB and this is common for 1TB disks. Probably the filesystem was purposely created smaller than it could be, but please confirm. The output of lsblk should be enough. – Kamil Maciorowski – 2017-06-13T06:58:37.427

oh yes you're right; these disks are 1TB each, I will edit my question; But somehow I need to allocate the missing >100GB ? – groovehunter – 2017-06-13T07:02:24.723

I don't know where this >100GB of yours came from. I think the btrfs filesystem will take up to 931.51GiB + 931.51GiB when it needs to. btrfs fi df can be confusing, I know. – Kamil Maciorowski – 2017-06-13T07:15:16.430

1I'm voting to close this question as off-topic because OP has answered the question in the body of the question – Dave – 2017-06-13T07:20:56.017

i would move the answer from body to answer in 2 days – groovehunter – 2017-06-13T07:35:29.970

@Kamil, the >100GB was also wrong assumption from me; I have a few mdadm raid 1 running and still think in terms of 1+1TB disks = 1TB space. sorry for confusion! – groovehunter – 2017-06-13T07:41:07.073

btrfs filesystem resize "no enough free space"

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