[Discuss] Linux file systems

[tmetro+blu at gmail.com (Tom Metro)]

Richard Pieri wrote:
> ...ext4...is...a poor choice. ext4 is unstable, it's buggy...

I'm not saying you're wrong, as I haven't investigated the matter
myself. I've certainly heard of Ext4 having bugs. But is this still
current information?

In tech we have a tendency to get turned off to technologies easily.
Particularly ones that we rely on for important things, like data
storage. (How often have we heard someone say they'll never use vendor
X's hard drive again, after having just experienced a drive failure?)
Are the sentiments towards Ext4 inertia from growing pains it had in its
early years, or are they an accurate reflection of where the code stands
today?

If there are still lingering problems, can anyone cite references? Are
they well documented, confirmed, and understood flaws? Are they problems
likely to be seen in the real world? (I ran across a report of an Ext4
bug recently, but it was only triggered under highly improbable
circumstances.) Or is it an aggregation of anecdotal reports saying the
file system is unreliable?

Are there fundamental architectural problems with Ext4?

If the file system is so problematic, what's your theory as to why many
distributions have chosen to stick with it?

What reasons did RedHat cite for favoring XFS over Ext4?


> It's that ext4 was end of life the moment Theodore Ts'o checked in the code...

What does that mean? Theodore Ts'o abandoned it? Or it was so far behind
the state-of-the-art represented by other current file systems that it
had no hope of catching up?

If the latter, that sounds subjective. Linux supports a lot of file
systems that all have various trade-offs. What makes sense on an
embedded device, a NAS, or a general purpose desktop will all be
different. Eventually we may come to use something like ZFS as a general
purpose file system on a desktop, but today that would be looked at as
overkill.


> ...the recovery tools (fsck, etc) are lacking...

In what way?


> ...it has no backup tools...

Not everyone agrees that it is necessary to have a filesystem-specific
backup tool.


> ...it's impossible to back out once an extent is used...

Why is that significant? Does it lead to greater fragmentation? Wasted
space?

 -Tom

-- 
Tom Metro
The Perl Shop, Newton, MA, USA
"Predictable On-demand Perl Consulting."
http://www.theperlshop.com/