Exactly. The thinking is that the base set of states will be fairly simple, and that capabilities such as suspend/resume will be described in extensions because it might not make sense for all implementations. -- Chris On 25/4/06 03:14, "Steve Loughran" <steve_loughran@hpl.hp.com> wrote:
Christopher Smith wrote:
Hi all,
Per Marvin's comments ...
Here is a pointer to the proposal for modelling job states that I made to the SAGA group last February.
http://www-unix.gridforum.org/mail_archive/saga-rg/2006/02/msg00107.html
-- Chris
Presumably suspend<-->resume is optional? That is, there are some things that cannot be suspended, or at least they suspend but cannot resume? (*)
That is something that is not in the CDDLM model (which is based on the WSDM state model), because its a lot harder t to suspend things like a database and a server hosting many active connections. Its a lot easier to shut it down and redeploy later, relying on the application to be able to continue when it is redeployed. Which is a good idea for anything you want to be resilient. [1]
If you have VM images you can suspend them, but at least as far as vmware is concerned, the apps don't get warned before and after, so they have a worse experience than on a laptop, where apps and drivers get warned that they are about to suspend and told that they have woken up. All you know about on a vmware hosted image is that the clock suddenly jumps and all your active TCP start throwing errors. You may have suspended, but the world still turns.
(*) Even on ACPI laptops there is evidence of a de-facto suspend state, S6: the sleep from which laptops do not recover. [2]
[1] http://swig.stanford.edu/~candea/papers/crashonly/ [2] http://www.hpl.hp.com/techreports/2000/HPL-2000-21.html .