Subject: Re: large inode numbers
To: David Laight <david@l8s.co.uk>
From: Bill Studenmund <wrstuden@netbsd.org>
List: tech-kern
Date: 12/17/2003 10:13:01
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On Wed, Dec 17, 2003 at 12:26:15AM +0000, David Laight wrote:
> On Tue, Dec 16, 2003 at 05:20:33PM +0100, Jaromir Dolecek wrote:
> > Martin Husemann wrote:
> > > I think it's time to bite the bullet and version struct dirent to giv=
e us
> > > large inode numbers. See PR kern/23773 for a trigger.
> > >=20
> > > Why didn't we do this a long time ago?
> >=20
> > Even today it's not ordinary to have filesystem which would
> > require 4G inodes. I'm not sure what's the inode size
> > nowadays, but you'd need at least 2048GB (with 512B per inode)
> > just to store the inode data.
>=20
> Well the default is 4 fragments per inode, you only need FFSv2 for
> more than 2^31 fragments - so any filesystem that needs FFSv2 is
> close to needing more than 2^31 inodes.
> (or if 2^31 inodes is way plenty, why do we need 2^31 fragments?)

Actually if you're playing the tertiary storage game, you can easily have=
=20
lots of inodes with 0 data and thus need more inodes than fragments. It's=
=20
a big tertiary storage system to do it, but it is not out of the question.

Take care,

Bill

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