[Spread-users] Unique name

Yair Amir yairamir at cs.jhu.edu
Sun Jan 29 15:20:43 EST 2012


Hi.

There is no such way. It is not clear how to specify such semantics
in partitionable environments, where due to network repairs and partitions
the "uniqueness" is not really determinable.

Spread provides a very informative membership service.

You can have both clients join a group "fred". It is guaranteed that
the order of clients in the group will be deterministic, and so based on
that order you can decided who really is "it".

This is a common way to implement hot backups. All join the group "fred"
and only the first in the list is the primary. Upon membership change,
each process checks to see which one is the primary.

Cheers,

	:) Yair.

On 1/29/12 5:17 AM, Andrew Holt wrote:
> Hi,
> 
> The scenarios is two (e.g. machines A & B) or more, communicating spread 
> servers.
> 
> A client connects as ‘fred’ to machine A, therefore his name is #fred#A.
> 
> A client connects as ‘fred’ to machine B, therefore his name is #fred#B.
> 
> Is there a simple way  I can make the second connect fail as there is 
> already a ‘fred’  
> 
> In other words make the name I connect with globally unique ?
> 
> Thanks,
> Andrew
> 
> =============================
> Andrew Holt
> 
> 
> Email: andrew.holt at 4asolutions.co.uk <mailto:andrew.holt at 4asolutions.co.uk>
> 
> =============================
> 
> 
> ------------------------------------------------------------------------
> 
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