Hi,
On Thu, Jul 12, 2001 at 04:26:28PM +0200, Samuel Graenacher wrote:
> I've just recently noticed that the ext3 projects is being actiavely
> maintained (again?). And looking at the new pages for 2.4.x it really
> made me interested. But I've got a few small questions I'd like
to
> clarify before I start to use it.
>
> 1) Tune2fs and mke2fs talk about a "default journal size"
that is
> depending on the partition size but don't give any example.
> How big would the default journal be on a 20gb partition?
The appropriate journal size has nothing to do with the size of the
filesystem --- the journal gets recycled once it fills, so the best
journal size is really a function of the rate at which you use it up
(ie. what your workload is like) and the speed of your disk rather
than the filesystem size. The default journal size should be fine,
although I'll probably do some testing later on to fine-tune the
journal sizes for different setups.
> 2) Is it possible to remove the journal again? I'm aware that you can
> use an ext3 partition with an ext2 kernel and have it completely
> ignore the journal but I'm wondering if I could completely get rid of
> the journal again if I don't like ext3? (without reformatting ;))
Sure. Just clear the "has_journal" flag on the filesystem, and e2fsck
will clear the journal out. debugfs will let you clear the flag.
> (The reason for me asking is that the partition is usually kinda low
> on space and say a 32/64mb log would waste valuable space)
Actually, I usually use a journal nearer to 10mb on a lot of my
filesystems.
> >From what I've read the the mailinglist archives tune2fs seems
to
> create a filename for the journal if used on a mounted partition.
> Would removing this file _cleanly_ remove the journal and make it ext2
> again? (doing that mounted as ext2 of course)
Sort of --- clearing the journal flag is much safer since it prevents
the kernel from thinking there's a journal and getting confused when
it doesn't find one.
Cheers,
Stephen