Subject: Re: Log area on-disk for the journal
To: Michael van Elst <mlelstv@serpens.de>
From: Bill Studenmund <wrstuden@netbsd.org>
List: tech-kern
Date: 10/23/2006 17:16:14
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On Mon, Oct 23, 2006 at 10:38:35PM +0200, Michael van Elst wrote:
> On Mon, Oct 23, 2006 at 01:21:33PM -0700, Bill Studenmund wrote:
> > On Mon, Oct 23, 2006 at 08:59:08PM +0200, Michael van Elst wrote:
> > > So how does the rest of the world do it?
> >=20
> > They probably have hooks and steps to cover the problems we're talking=
=20
> > about.
>=20
> My guess is that, at least for Solaris, the journal isn't used
> to allow operations that can't be recovered by fsck. The operations
> are identical, wether logging is enabled or not.

But that's the point of journaling.

Making operations fsck'able means doing the whole operation as a sequence=
=20
of steps and waiting for individual steps to be written before continuing.=
=20
The point of journaling is to get around the sequence; we do the whole=20
thing at once and use a two-stage commit to make it safe.

So the "journaling" that would match what you describe above isn't really=
=20
journaling.

Take care,

Bill

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