Is there a Linux filesystem like 'tee'? [closed]

Solution 1:

I have found ChironFS.

It is a FUSE based filesystem. Its main purpose is to guarantee filesystem availability using replication. But it isn't a RAID implementation. RAID replicates DEVICES not FILESYSTEMS.

Important: I haven't used it. I cannot guide you further at this moment. I know this makes my answer mediocre quality at most.

Still, considering your case I have a general doubt. Any experiment with btrfs-specific features (like COW) would require one of the two:

• the "proxy filesystem" ability to pass it to underlying btrfs and to replicate/simulate/fake it with ext4 (e.g. simple copy instead of COW) in a smart way; but FUSE implements just common operations (like open, chmod, mkdir) in a custom way, this does not include btrfs-specific operations;
• direct access to btrfs (bypassing "proxy filesystem"), but this would easily break one-to-one correspondence to ext4.

For these reasons I think every existing solution (ChironFS or something else, if any) will not allow you to freely experiment with btrfs, unless it is written with btrfs in mind from the start. I've never heard of such a thing.