Re: [dev] JFS filesystem

From: Daniel Cegiełka <>
Date: Sun, 21 Apr 2019 14:53:19 +0200

niedz., 21 kwi 2019 o 14:35 Martin Tournoij <> napisał(a):
> On Fri, 19 Apr 2019 09:20:41 +0200 Daniel Cegiełka <> wrote:
> > * ZFS
> > Resource-consuming. Designed for large servers.
> >
> > * btrfs
> > Rather a good choice for server rooms (Facebook).
> >
> > * bcachefs
> > A good competition for btrfs/ZFS.
> One thing that ZFS offers that most other filesystems don't is very strong
> data consistency guarantees. This is important especially if you plan to
> store data for any length of time. Turns out storing data for years or even
> decades is actually quite hard, due to generic bit rot (hardware failure,
> cosmic rays, etc.) even when using mirrored RAID.
> In fact, in many filesystems there are very weak – or no! – guarantees that
> the data you're reading is actually correct. Systems like ext4 simply assume
> that the data written to the disk will never change. AFAIK, it has
> essentially no mechanism at all to deal with silent data corruption.
> Unfortunately, there are also many downsides to ZFS; the license, much bloat
> ("kitchen sink and then some"), performance on "old" hardware, etc.
> At a glance, btrf also seems to have *some* data consistency guarantees,
> although I'm not sure if they're as good as ZFS. Besides, btrfs doesn't seem
> stable as a general purpose filesystem[1], and I'm not sure if it'll ever
> be.
> I had never heard of bcachefs before, but it seems interesting. Checksums
> are done per file (extent)[2] rather than per block (which is what ZFS
> does), which will make data recovery harder after corruption. Still, it's
> better than ext4 or JFS (which has no checksums at all). According to the
> Patreon homepage it seems to be in the early stages of being stable.

> Yikes(?)
> Conclusion: bcachefs is probably the future(?)

The good news is that this file system is very positively rated by the
kernel developers and will probably go to the mainline soon. I also
think that bcachefs is the most interesting option. ZFS, btrfs and
bcachefs are, however, designed as a filesystems for data storage.
These are good filesystems for databases. Next to this is the daily
work, where ext4 looks best - so bit rot is not a huge problem vs mem
errors etc. Unfortunately, ext4 is three file systems in one. That's
why I'm mainly looking for an alternative to ext4, and here JFS looks
quite interesting.

> [1]:
> [2]:
Received on Sun Apr 21 2019 - 14:53:19 CEST

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