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From: Sam Leffler <sam@errno.com>
Organization: Errno Consulting
To: Nate Lawson <nate@root.org>
Date: Thu, 22 Jul 2004 13:00:11 -0700
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cc: Peter Jeremy <PeterJeremy@optushome.com.au>
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On Thursday 22 July 2004 09:29 am, Nate Lawson wrote:
> Peter Jeremy wrote:
> > On Wed, 2004-Jul-21 15:57:30 -0600, Scott Long wrote:
> >>Implementing a journalling filesystem would be a much more beneficial
> >>use of time here.
> >
> > You still wind up with unwritten data in RAM, just less of it.
> >
> > How much effort would be required to add journalling to UFS or UFS2?
> > How big a gain does journalling give you over soft-updates?
>
> Kirk pointed out something to me the other day which many people don't
> think about.  None of the journaling systems has had its recovery mode
> fully tested, especially on very large systems (dozen TB).  It turns out
> that memory pressure from per-allocation unit state is a big problem
> when you are trying to recover a huge volume.
>
> Just because it says "journaling" doesn't make it good.

I can assure you that XFS has been well-tested with TB systems.

	Sam