Re: Re: New Linux xfs/reiser file systems

> On Fri, May 04, 2001 at 08:02:17AM -0400, mlw wrote:
> > The way I understand it is that ReiserFS does not attempt to separate files at
> > the block level. Multiple files can live in the same disk block. This is cool
> > if you have many small files, but the extra overhead for large files such as
> > those used by a database, is a bit much.
> 
> It should be at least as fast as other filesystems for large files. I suspect
> that it would be faster in fact.  The only catch is that the performance of
> reiserfs sucks when it gets past 85% or so full. (ext2 has similar problems)

That is pretty standard for most modern file systems.  They need that
free space to optimize.


> 
> You can read about all this stuff at http://www.namesys.com/
> 
> > I really think a simple low down dirty file system is just what the doctor
> > ordered for postgres.
> 
> Traditional BSD FFS or Solaris UFS is probably the best bet for postgres.

That is my opinion.  BSD FFS seems to be general enough to give good
performance for a large scale of application needs.  It is not as fast
as XFS for streaming large files (media), and it doesn't optimize small
files below the 1k size (fragments), and it does require fsck on reboot.

However, looking at all those for PostgreSQL, the costs of the new Linux
file systems seems pretty high, especially considering our need for
fsync().

What I am really concerned about is when xfs/reiser become the default
file systems for Linux, and people complain about PostgreSQL
performance.  And if we require special file systems, we lose some of
our ability to easily grow.  Because of ext2's problems with crash
recovery, who is going to want to put other data on that file system
when they have xfs/reiser available.  And boots are going to have to
fsck that ext2 file system.

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