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Re: [xmlblaster] Mirrored Masters?

Hi David,

multi master is not implemented.

The I_LoadBalancer#getClusterNode() returns one node (NodeMasterInfo) which
is used to forward messages to the next node, but only to one.

If you need mirroring you could, depending if you need "failover" or "load balancing",
consider following:

1) Change the xmlBlaster cluster code to handle multiple masters
You need to decide in this case if the multiple masters are informed
in a transaction (sync) or not (async). Clients need to be coded
to choose a master depending on current load or failure.
-> failover and load balancing

2) You could create an extended I_Queue and I_Map plugin which
duplicates the data to two DBs
-> failover

3) You could do low-level DB mirroring (DRDB, Linux HA et al)
xmlBlaster gets on startup all information to re-establish its state.
In this case the mirrored xmlBlaster is started on failure of the first,
clients automatically find the mirrored as the IP is change (standard HA behaviour)
-> failover

4) Master/Slave operation (exists already, one master with many salves)
-> load balancing

5) Combination of 3) and 4) should work out of the box
-> failover and load balancing


It depends on what you want to achieve,

best regards
Michele
Marcel


David R Robison schrieb:
In the discussion on clustering in the reference manual it talks about mirrored masters:

    /An xmlBlaster cluster allows to have more than one master server
    for a specific message domain. The master nodes are //mirrored
    instances for those messages. Published messages reach all master
    nodes. Subscribed messages are retrieved using a load balance
    algorithm.
    /


However, the discussion says that it has not been implemented. Has any work been done on this? Any suggestions on how to achieve this?
Thanks, David
--

David R Robison
Open Roads Consulting, Inc.
103 Watson Road, Chesapeake, VA 23320
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--
Marcel Ruff
http://www.xmlBlaster.org
http://watchee.net
Phone: +49 7551 309371