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What about the whole market of 'lemons' theory http://www.brillig.org/people/acd/lemon.html and how it applies to the used car market - isn't it impossible to get a decent used car because of this?

Here's an Ext4/XFS/ZFS benchmark

I would like to see a more recent benchmark that did include JFS/Reiser/etc, though.

One of many reasons right here

I messed around with Ext4 for a little while on my machine (Like a couple days, just toying with it and seeing how its performance compares to Ext3 and Reiser4) a while back, like maybe a little bit before it was merged as experimental in the mainstream kernel. It is fast, backwards-compatible and extremely featureful. XFS is not a bad filesystem, but it has some problems, in my eyes. Metadata-only journaling, aggressive caching that makes it a potentially dangerous choice if you don't have a UPS, very slow metadata and deletion operations.

That's great that XFS has a lot of features Ext4 is bringing to the playing field, and has had them for a long time. To pretend, however, that the developers of Ext4 simply have a NIH syndrome is just silly and disregards the fact that there is a lot that Ext4 already provides that XFS doesn't, and even more that it will soon. You might not see what the big deal is, but really, I can assure you that it won't be very long before the new ideas Ext4 employs are in widespread use.

Here's an interesting article that really caught my eye with this: "Storage snapshot: The financial firm has more than 14 Petabytes of active storage and plans to add "several more Pbytes" within the next 12 months."

To be honest, Ext4 looks promising. But....

1) Ext3 isn't a bad filesystem. It performs just average over most tests. And that is a _good_ thing, it doesn't excel at any big thing but also doesn't completely suck at any big things (Reiser: large files, sparse files). It makes a good general use filesystem and has excellent tool chains available for it.

2) Ext4 is only non backward compatible in its on disk layout if you enable extents. This is a moot point, though, since extents will be the default (they improve performance).

3) Ted Tso is leading the development. I trust him, Ext2 and Ext3 haven't let me down yet. In the real world, data is money and I prefer safety over performance. Yes I even disable that 32MB write back cache. YMMV.

4) Ext[34] gives me three journaling options (journal, ordered, writeback). No other linux filesystem offers this.

5) Ext4 will offer greatly improved fsck times, online defragmentation, etc (online defrag has me drooling).

As for overall performance, not bad at all:

here
here
here

To quote:

> Short version: ext4 is awesome. zfs has absurdly fast metadata
> operations but falls apart on sequential transfer. xfs has great
> sequential transfer but really bad metadata ops, like 3 minutes to tar
> up the kernel.

Its good that Ext4 is bringing some good change... The part I'm most excited about, it appears Ext4 will be just as good as Ext3 in being a good general purpose filesystem. I can expect average to good performance across the board.

IMHO

Waiting in line for checkin at 365 Main:

http://tastic.brillig.org/~jwb/dorks.jpg

They're not the speediest at letting you in at 365... this was taken about an hour ago from across the street: http://tastic.brillig.org/~jwb/dorks.jpg