both soft updates and journalling are designed to solve the same problem. both have their own merits but i don't think they can be directly be compared as apples to apples. we can, however, directly compare a variety of journalling filesystems which i think would be another different "religious" discussion. :)
speaking of fsck , it was admitted by the *BSD community that fsck does not scale well on larger file storage capacities (TeraBytes): http://www.freebsd.org/news/status/report-jan-2005-mar-2005.html#Filesystem-journalling-for-UFS .... "It's time to bite the bullet and admit that fsck is no longer scalable for modern storage capacities. While a healthy debate can still be had on the merits and data integrity guarantees of journalling vs. SoftUpdates, the fact that SoftUpdates still requires a fsck to ensure consistency of the filesystem metadata after an unclean shutdown means uptime is lost. While background fsck is available, it saps system performance and stretched the fsck time out to hours." -- Scott Long (FreeBSD) .... but now, journalling is supported on FreeBSD (via gjournal) and would be supported on _NetBSD_ (via JFFS) : http://www.freebsd.org/news/status/report-apr-2006-jun-2006.html#GJournal http://www.netbsd.org/contrib/projects.html#j-ffs http://www.netbsd.org/Foundation/press/soc2006-summary.html anyway, here's an updated presentation on Linux Kongress 2006 wherein a "real-world" performance benchmark was conducted between journalling vs soft updates using various filesystems and OSes: http://bulk.fefe.de/lk2006/talk.pdf On 2/5/07, Paolo Alexis Falcone <[EMAIL PROTECTED]> wrote:
> On Mon, 2007-02-05 at 17:30 +0800, Keech Angelo Famorca > <[EMAIL PROTECTED]> wrote: > > > IMHO Linux have yet to have a stable filesystem. I think this is just flame bait... <fanning the flames>anything that still needs a full fsck to recover from a crash is no stable filesystem for me.</fanning the flames> Kidding aside, soft updates is still a young concept (McKusick's paper on it was released in 2000, with a FreeBSD implementation merged in 2002) which has been into BSD UFS for the last four years. Journalling on the other hand, has been in Unix implementations for a very long time already, and has already proven its worth regarding stability. The likes of ext3, XFS and JFS have been in Linux for roughly the same amount of time, with the latter two being in commercial Unix for an even longer period of time. We all do know of the disadvantages of FS journals though ... which soft updates aimed to skirt around. -- Paolo Alexis Falcone [EMAIL PROTECTED]
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