Manjaro KDE btrfs filesystem size

[vagrous101]

Hi, I had installed Manjaro KDE 21.1.1 on a 250 GB SSD and updated till I broke the system (due to my fault). So I installed Manjaro again, but to my surprise, I found that the installation size is much more in today’s install. How can that be possible? (I installed almost the same set of software) Am I getting something very wrong?
Previous:

Present:

[Strit]

1.5 GB’s can be almost anything, like cache, logs, package cache etc.

[navtey]

Btrfs is COW (copy on write) , So when you create snapshot , it creates a separate instance at that time, and not stores data twice. Whenever anything new is added it is added “over” the previous instance.

What you see in Size is , size of snapshot, not how much size of data that was had to be stored on disk for that snapshot, that is shown in unshared portion, which you can clearly see is merely 13.7mb + 344.1kb.

You can also verify this by mounting the drive in the folder , and doing

btrfs filesystem du <timeshift-snapshot>

[vagrous101]

I cleared all the user cache and pacman cache before creating the snapshots, before creating the snapshots.

[vagrous101]

So is there any way I can see what is the actual occupied disk space and how much disk space is free?

[navtey]

Something like this can help you crosscheck , in case you have doubts for each particular snapshot.

@vagrous101

So is there any way I can see what is the actual occupied disk space and how much disk space is free?

This is an interesting question, most popular tools usually don’t report correct due to btrfs COW feature and they might think data has been copied twice while it’s not

btrfs-progs which is already installed provides utilities to manage that,

in order to check usage of any folder use

sudo btrfs filesystem du --mbytes -s <Folder_Path>

du = disk usage
–mbytes = report it in mb
-s = don’t tell me usage of every file , rather summarize it

You can also check how much disk is free/or check total usage by simply using

sudo btrfs filesystem usage /

[vagrous101]

Thanks a lot for clearing my misunderstandings.

[andreas85]

This is not as easy as it looks, because btrfs may have compressed some files. Some may be linked together. There may be snapshots …
This will show the real size and space of btrfs fast

sudo btrfs filesystem show /

Label: none  uuid: 3487ba3d-1cba-4cdc-a043-c420ebca2aca
	Total devices 2 FS bytes used 418.94GiB
	devid    1 size 900.00GiB used 470.03GiB path /dev/sda2
	devid    3 size 900.00GiB used 470.03GiB path /dev/nvme0n1p3

If you want btrfs to count all the beans this will take a while

sudo btrfs filesystem du --summarize / 

     Total   Exclusive  Set shared  Filename
...