Re: Journalling filesystems

[Marcus Brinkmann]

At Thu, 17 Jun 2004 00:01:51 +0200,
marco_g wrote:
> 
> Ludovic Courtès <ludo@chbouib.org> writes:
> 
> > Today, 3 hours, 44 minutes, 10 seconds ago, Marcus Brinkmann wrote:
> >> I also have the feeling that there are other designs that can provide
> >> an alternative or supplement to this (mmh, persistence?
> >> check-pointing?  Versioning?)
> >
> > Yes, persistence (ie. application and kernel state checkpointing and
> > rollback operations) is, in my opinion, one of the coolest things since
> > sliced bread.  ;-)  Linux 2.6 actually has so-called "software suspend"
> > which is exactly that.
> 
> How does "software suspend" save you from a crash?  Same for those
> other features mentioned?  I am not that familiar with it.

In a persistent model, you don't have a filesystem.  Everything is
kept in memory.  The system makes snapshots of all the memory and
state once in a while, and if you crash you go back to the latest
snapshot.

Updating such a system is an interesting task :) but it can be done
via live-updates.  Pretty cool, if you can get it.

Marcus