Ryusuke Konishi, thank you again for the detailed explanations! On Thu, Feb 6, 2025 at 3:08 PM Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx> wrote: > Generally speaking, copy-on-write file systems such as ZFS and Btrfs > are newer. The concept of LFS (Log-structured File System) itself was > proposed in 1988 and implemented in UNIX in 1992. It is an old method, > and I believe there are few surviving implementations today. In that > sense, I used the word "legacy". Haha, but we’re still using lots of old methods around today, such as UNIX and UNIX-like systems. > > High frequency snapshotting is something I am missing from other > > file systems. > > That may be true, but frequent snapshots are in principle possible in > copy-on-write filesystems (apart from the actual support), while > retroactive snapshots (the ability to turn each checkpoint into a > mountable snapshot at a later time) are unique to NILFS. I should’ve used the term “high-frequency checkpointing”. As an end user, the only difference between checkpoints and snapshots I see is that snapshots won’t be deleted by GC.
