Compression on f2fs system volume

Issues & Assistance
1

I’ve been using f2fs on my nvme system drive for quite a while now, I know that it supports compression, in CachyOS at least lz4 and lz4hc - other methods for some reason are not displayed in the parameters, and this is even included in fstab:

❯ modinfo f2fs | grep compress

depends: lz4_compress,lz4hc_compress
parm: num_compress_pages:Number of intermediate compress pages to preallocate (uint)

~
❯

defaults,compress_algorithm=lz4,compress_chksum,gc_merge,lazytime 0 1

But for some reason the volume itself is created during the system installation via Calamares without the option to enable compression, so compression does not work. Is this a bug or a feature? :slight_smile:

2

Hi,

Be aware, that f2fs compression does not actually reduce the file/storage size. We do not enable it currently, since there were problems in the past and also needs to be modified in calamares for a proper integration.

3

data compression isn’t about file size, it’s about improve read and write, and save space for inline data

4

how to enable compression https://www.kernel.org/doc/Documentation/filesystems/f2fs.txt
you must scroll down to the end of the page

5

Thanks for your reply, very useful information. But shouldn’t the volume be formatted with compression option initially? For example, like this:

sudo mkfs.f2fs -f -c lz4 /dev/sda2

6

it should according to the arch wiki but nothing ever happen.

 sudo cat /sys/kernel/debug/f2fs/status | grep compress
  - compress:    0, hit:       0
7

So even if you create a volume with the compression option, the files still aren’t compressed? Unfortunately, at the moment I don’t have any free volumes to try to implement this.

8

unfortunately without compression :frowning:
i created the volume in summer 2022 and until now:

sudo cat /sys/kernel/debug/f2fs/status | grep compress
  - compress:    0, hit:       0
10

compression works when:

  1. filesystem was created with: -O extra_attr,inode_checksum,sb_checksum,compression
  2. and mounted with: compress_algorithm=lz4,compress_chksum,compress_extension=*
sudo cat /sys/kernel/debug/f2fs/status | grep Compress
  - Compressed Inode: 8968, Blocks: 138322