perfsonar development work

[Maciej Glowiak <>]

Nicolas Simar wrote:
> Maciej Glowiak wrote:
> > Hi Nicolas,
> >
> > Nicolas Simar wrote:
> >
> > > What would happen in the single LS instance it needs to register with 
> > > is down?
> >
> >
> > Java exception is thrown, because connection to the server (perfSONAR 
> > service) cannot be established.
> >
> > > What will happen with the info (will it dissapear, does the service 
> > > has to find out another single LS?)
> >
> >
> > LS info that is to be registered with the LS?
> >
> > It will disappear (in fact client won't send it, because it won't be 
> > able to establish connection to the server).
> >
> > All other data in LS will be kept in database even if the service is 
> > down.
>
> This implies that in the model, all the LSes have all the information 
> about everything is it? (no redirection from one LS to the one where the 
> service initialy registered to get more information are planned?)
>
> Isn't there a timer after which the other LSes will start removing the 
> information from the "down" LS?
>
> Cheers,

Hi Nicolas,

I think I don't understand your question in that context.
I'll try to summarize. By LS I mean single-domain-LS.

1. If LS that is contacted by a client is down, the client will get
   Exception. Then the client may contact "the redundant LS" if there is
   any (there is not for now).

2. Usually each service registers to only "ONE" LS. If the LS is down,
   lookup information of the service won't be registered anywhere

3. So, usually all LSes have disjunctive set of registered services

4. If information was not found in one LS it won't redirect client to
   another LS (because it doesn't know about any other LS)

5. There is a timer in LS. All lookup information registered in LS are
   time-stamped and after defined TTL are removed. (they're time-stamped
   with all update operations: re-registration or keepalive)

Multi LS would resolve some of these problems.

I hope now it's more clear.

Maciej