lkml.org 
[lkml]   [1999]   [May]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: XFS and journalling filesystems
Date

----- Original Message -----
From: Andreas Bogk <andreas@andreas.org>
To: Jeff Merkey <jmerkey@timpanogas.com>
Cc: <linux-kernel@vger.rutgers.edu>
Sent: Tuesday, May 25, 1999 10:37 AM
Subject: Re: XFS and journalling filesystems


> "Jeff Merkey" <jmerkey@timpanogas.com> writes:
>
> > Journalling slows everything down because it requires all writes (and
reads)
> > to be serialized. This decreases SMP parallelism. The last thing Linux
> > needs is another slow SMP poor component. I think more is better, don't
get
>
> This may be true for some implementations, but not XFS. It uses
> multiple trees for FS resource management, so every CPU can just grab
> one of the trees and go ahead. SGI does have some nice SMP machines,
> and they are aware of the problems with that.
>

Sorry, I've been doing SMP for about 12 years, and it isn't this simple.
Grabs "one of the trees". What happens if they are sharing open files or
two processors try to share the tree? Linux doesn't have decent shared sync
objects, how do they implement r/w locks, do they provide them in the file
system, or does Irix have its own unique ones? The log file (journal is
SINGLE threaded [it has to be on a journalling file system]). There's a lot
of issues with mapping a **REAL** SMP file system to Linux. Linux needs a
lot of SMP work to support these types of technologies with some decent
scaling and an expanded set of sync primitive. I've got $100.00 that says
it will be **SLOWER** than ext2, and the scaling will be dismal. Care to
take the bet?

Jeff

> > me wrong. I jsut didn't like seeing some folks go belly up and start
> > killing their internal projects (like ext3) just becuase XFS shows up on
the
> > scene. Particularly since it was a patently blatant predatory move by
SGI
> > based on pure politics -- so obvious. It's also just another unix file
> > system, and comes with all the limitations of Unix FS's.
>
> As long as SGI shows neither code nor license, this point is moot
> anyways. But XFS scores pretty well for a jounaling file system, or
> just about any Unix file system currently available.
>

Let's see if their lawyers are really going to let them give away their IP
with no strings attached. This will be interesting.


Jeff


> Andreas
>
> --
> Reality is two's complement. See:
> ftp://ftp.netcom.com/pub/hb/hbaker/hakmem/hacks.html#item154
>


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:51    [W:0.241 / U:0.152 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site