OLS Checkpoint/Restart BOF Summary
haveblue at us.ibm.com
Fri Jul 6 09:35:26 PDT 2007
First of all, thanks to everyone that attended the BOF. It was very
First thing, does anyone have a small, working checkpoint/restart
implementation that is mostly or all in userspace that is easy to build
on and extend? If not, I'll probably continue hacking on the one that I
have, or go try to steal something from one of the other projects.
One of the developers of bproc attended. They use an in-kernel
mechanism called vmadump to migrate processes between nodes in a
cluster. However, they only move processes in very particular states,
such as with no sockets open.
Eric Focht from NEC attended. They're using a mechanism called KDDM:
to share kernel structures and user memory (among other things) across a
cluster. This allows processes to be migrated, but requires heavy
Several OpenVZ/Virtuozzo developers attended.
Some Kerlabs developer attended.
Everyone seems to want to do as much as possible of checkpoint/restart
in the kernel. Dave Hansen lobbied for doing as much in userspace as
possible, at least until we've proved exactly what is really hard (or
impossible) in userspace but easier in the kernel. That way we have
some actual justification in order to get patches merged into mainline.
Surprisingly, no one really disagreed with this sentiment.
Does anyone want to say something about networking developments?
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