Re: Reliability of RPC services

[Michal Suchanek]

On 4/25/06, Jonathan S. Shapiro <address@hidden> wrote:
> On Tue, 2006-04-25 at 11:54 +0200, Michal Suchanek wrote:
>
> > ad (b) Imagine a few  scenarios:
> > ...
> > And I do not think that timeouts or watchdogs solve [these] on non-realtime 
> > system.
>
> I agree. However, this mis-states the issue. You are talking about what
> happens when you have already decided to recover (e.g. by killing a
> non-performing renderer). The purpose of the timeout is to help
> determine when recovery is required.
>
> Also, in each of the examples that you gave, an asynchronous interface
> is appropriate. Recovering on an asynchronous interface is relatively
> straightforward.
>

So you say that the timeouts and watch dogs actually solve a different
kind of problem.

The send-once + reference-counted capabilities serve to notify when a
service has already failed. This allows the client to restart the
action or use different means for obtaiing the service. Or just free
any resources associated with the failed service in case of a proxy.

But the watchdog is used to identify a service that is slow to respond
and may be the one that is failing so that the user may remove it and
trigger the recovery.

Thanks

Michal