Hacker News Reader

Comment by DiabloD3 | Hacker News Reader

I think you meant ZFS, not zsh.

I use both XFS and ZFS. XFS in any situation where it is a single drive (ie, my laptop), ZFS in any situation where I'm doing actual fault tolerant high performance storage stuff.

I don't see where ext family really matters in modern storage. If I decide to not use XFS anymore, there are flash-dedicated filesystems that will beat ext in performance and reliability on SSDs that better fit the future.

View on HN

ZFS is actually ideal for single drives because even if you can't do recovery, knowing a file has corrupted is extremely valuable.

set copies=2 or 3 and it can recover corrupted data on that filesystem at the expense of storage

SSDs are very likely to put all those copies into a single physical block underneath. Since ZFS makes backups easy, better stick to copies=1 and do backups often.

I shouldn't think that's true. Why wouldn't the firmware be splitting writes across different physical chips for performance and wear leveling reasons?

Wrong. ZFS' copies are made across several different devices.

(2nd copy)

If you are using ZFS on a single drive, they reside on the same drive by necessity. Which was the case the parent posters were talking about.

Wrong. ZFS' copies are made across several different devices.

What do you mean? The discussion in this particular sub-thread is about running ZFS on a single drive (think laptop). Does it have some kind of mechanism to send the write for a copy "later enough" that it will likely end on a different physical block?

I meant "primarily this copies mechanism is targeted towards multiple devices setup".

With a single SSD it's indeed prone to the caveat which was pointed out; even if not due to being mapped to same storage "area" but also because SSDs often fail completely.

Also makes sense to note that __when__ narrowed to a single-disk setup ZFS' can be interchanged with Btrfs; almost same set of features but lesser overhead and complexity.

Single drive ZFS is also a great use case for ZFS because:

- full data integrity check (not only metadata like with XFS)

- transparent compression (LZ/ZSTD/...)

- ZFS Boot Environments - makes your system bulletproof against changes

- easy move ZFS Boot Environments between systems with zfs send|zfs recv commands

None of that is possible with XFS.

> there are flash-dedicated filesystems that will beat ext in performance and reliability

If you mean f2fs, it really won't. Be careful with it.

https://www.usenix.org/system/files/atc19-jaffer.pdf

The paper is old at this point, but I found a fresh PhD thesis from the same author from 2023, and it seems to re-confirm these findings.

That sucks. I know a lot of Android users that prefer f2fs over ext* due to reliability and performance concerns, and seem to at least have some concrete reason to believe so.

Fixed, thank you!

Reply on news.ycombinator.com