Re: Removing softdep

[Joerg Sonnenberger <joerg%britannica.bec.de@localhost>]

On Sat, Jun 07, 2008 at 12:11:57AM +0100, Andrew Doran wrote:
> After 5.0 is branched we're planning to merge in the ffs journalling code
> contributed by Wasabi. It could use some performance improvements on
> multiuser systems, and maybe a few other tweaks like auto-creating the
> journal. However, it _is_ known to meet its data integrity promises, and is
> a much easier code base to maintain and work with.

From the perspective of having it used on a Dual Core machine doing
pkgsrc builds for a while, I think the performance issues are overrated.
There's one big dead lock bug pending, but wapbl has been extremely
stable otherwise.

Read: under the heavy IO of a bulk build, it will lock against itself
after a while, but it never lost data that way.

What needs investigation is ensuring that basic data reliability issues
are handled. For example, when crashing with wapbl during a bulk build,
you will see random content in the files and I am not sure whether this
can't result in exposure of sensitive data. To this degree it might be
needed to teach wapbl some ordering constraints (like softdep uses).

Otherwise I completely agree.

Joerg