[Re] Web Clustering : Stick Sessions with Shared Store

[gianny DAMOUR <gi...@hotmail.com>]

Jeremy Boynes wrote:

>However, as Andy says, the cost of storing a serialized object in a BLOB is
>significant. Other forms of shared store are available though which may
>offer better performance (e.g. a hi-av NFS server).
Do we need a shared repository or a replicated repository?

>The issue I have with hb's approach is the reliance on an Admin Server, of
>which there would need to be at least two and they would need to co-operate
>between themselves and with any load-balancers. I think this can be handled
>by the regular servers themselves just as efficiently.
I agree. It seems that in such a design an Admin Server is only used to 
route incoming requests to the relevant node.

However, I do not believe that regular servers can do this job. I assume 
that they will implement a standard peer-to-peer cluster topology to provide 
redundancies, however I do not see how they can handle the dispatch of 
incoming requests.

This feature seems to be either a client or a proxy one: I mean it should be 
done prior to reach the nodes.

For instance, this feature is treated on the client-side via a stub aware of 
the available nodes in WebLogic. It seems that JBoss (correct me if I am 
wrong) has also followed this design.

>I am also not convinced it reduces the amount of net traffic. After each
>request the MS must write to the shared store, which is the same traffic as
>a unicast write to another node or a multicast write to the partition
>(discounting the processing power needed to receive the message).
I agree. However, this is based on the assumption that only one unicast 
write is required. In other words, this is a primary/secondary topology. I 
think that hd did not intended such a topology and hence his statement.

Gianny

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