Re: Background fsck

[Gary Thorpe <gathorpe79@xxxxxxxxx>]

Dan Melomedman wrote:

> Gary Thorpe wrote:
>
>
> > I think ext3 would be easiest (ext2 is already available across the 
> > BSD's), but not technically the best. I think ReiserFS wants to grow 
> > into a database or some unified name space so..... What I would be 
> > interested to know if implementing some of them under a BSD license 
> > might peeve the original owners?
>
> Can't do it with ReiserFS (License? Documentation?) since they want to
> be paid to port it. They also want to be paid twenty-five dollars to ask
> them a question. They are full of it. It took them many developers and
> years to get where they are now, and their attitude towards stability
> issues is known to be "Oh, you made a back up, right?". They do use very
> novel ideas though obviously. It's great to be able to have scalable
> directories (millions of files). Email servers wouldn't need directory
> splits for their queues with this feature among many other uses.


I have also heard of problems with stability/data loss, but I didn't 
want to comment because I have never really tried it (or any of Linux's 
journaling options). This is another major issue with ReiserFS: it looks 
nice on paper but does it deliver? If it doesn't, there is not much 
point in trying to use it.

> But there are also XFS and JFS to consider. Both are probably GPL
> though.


These deliver (i.e. have been proven on at lest the original platforms), 
but with these and ReiserFS I would expect resistance to a BSD-licensed 
implementation. Whether it would be anything more than a philosophical 
objection is something a lawyer would have to look into.

As someone else pointed out, I was more inclined towards using the GPLed 
versions of these file systems to generate specs and reimplement them 
for BSD. The problem with ext2/ext3/FFS is that the way they work is not 
the most modern: newer file systems can allocate inodes on demand, 
support extents, large directories, dynamic resizing (both increases and 
decreases in size), and faster operation (this is debatable for 
single-user systems). So in my thinking it would be nice to improve on 
all of these things if you are developing/porting a new file system.

But since ext2 has a BSD implementation and ext3 is based on ext2, this 
should be the easiest route. I have also read that the journaling 
implementation for ext3 is applicable to other file systems, so 
implementing it may make journaling for FFS possible as well (I think 
Sun and Apple already have implemented journaling/logging for FFS in 
Solaris and MacOS X respectively?).