Re: Improving RAIDframe Parity Handling: The Diff

[Matthias Scheler <tron%zhadum.org.uk@localhost>]

On Tue, Oct 20, 2009 at 04:53:59PM -0400, Jed Davis wrote:
> Note in particular that, with the patch, a parity map will be used by
> default with any non-RAID-0 set.  As far as compatibility with
> non-parity-map kernels, I spent a fair amount of time on this and it
> should Do The Right Thing -- the parity map is in addition to the
> existing global dirty bit which is maintained as before, and if the
> previous kernel to touch the RAID was not parity-map enabled, a
> parity-map kernel will detect this and disregard the parity map.

That sounds like a reasonable approach. How does a kernel with
parity map support detect that there is no parity map present on disk?

> Another test of 10 parallel pkgsrc-untarrings, went up to 9.8GB.

My server should be able to synchronise that in about two minutes
which is great improvement over the two and half hours in need now.

> Comments and questions (and testing) welcome.

From your patch it looks like it would be feasable to pull this
up into the "netbsd-5" branch. Can you see any reason why that
would not be possible?

        Kind regards

-- 
Matthias Scheler                                  http://zhadum.org.uk/