Messages in this thread | | | Date | Sun, 22 Jan 2006 20:50:39 +0100 | From | Diego Calleja <> | Subject | Re: soft update vs journaling? |
| |
El Sun, 22 Jan 2006 04:31:44 -0500, Theodore Ts'o <tytso@mit.edu> escribió:
> One major downside with Soft Updates that you haven't mentioned in > your note, is that the amount of complexity it adds to the filesystem > is tremendous; the filesystem has to keep track of a very complex > state machinery, with knowledge of about the ordering constraints of > each change to the filesystem and how to "back out" parts of the > change when that becomes necessary.
And FreeBSD is implementing journaling for UFS and getting rid of softupdates [1]. While this not proves that softupdates is "a bad idea", i think this proves why the added sofupdates complexity doesn't seem to pay off in the real world.
[1]: http://lists.freebsd.org/pipermail/freebsd-hackers/2004-December/009261.html
"4. Journaled filesystem. While we can debate the merits of speed and data integrety of journalling vs. softupdates, the simple fact remains that softupdates still requires a fsck run on recovery, and the multi-terabyte filesystems that are possible these days make fsck a very long and unpleasant experience, even with bg-fsck. There was work at some point at RPI to add journaling to UFS, but there hasn't been much status on that in a long time. There have also been proposals and works-in-progress to port JFS, ReiserFS, and XFS. Some of these efforts are still alive, but they need to be seen through to completion" - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |