Re: [RFC] TileFS - a proposal for scalable integrity checking

["Jörn Engel" <joern@lazybastard.org>]

On Sun, 29 April 2007 18:34:59 +0200, Andi Kleen wrote:
> Matt Mackall <mpm@selenic.com> writes:
> 
> > This is a relatively simple scheme for making a filesystem with
> > incremental online consistency checks of both data and metadata.
> > Overhead can be well under 1% disk space and CPU overhead may also be
> > very small, while greatly improving filesystem integrity.
> 
> Problem I see is that your scheme doesn't support metadata checksums only.

Why?  It is fairly simple to run many different schemes with this:
- Generate checksums for everything, compare for each access.
- Generate checksums for everything, only compare metadata checksums.
- Generate checksums for everything, only compare at fsck time.
- Generate metadata checksums, use 0x0000_0000 as data "checksums".
- Not generate any checksums.

Users without checksums would still pay the .1% space overhead, sure.
I'd bet they already pay more for unused inodes.

Jörn

-- 
ticks = jiffies;
while (ticks == jiffies);
ticks = jiffies;
-- /usr/src/linux/init/main.c
-
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html