Communication
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Between Components
Each PortalProtect Component uses the Peer2Peer communication method – this can be compared to RMI, in the sense that a peer sends a command to another, which executes it and optionally sends a reply. The data being sent is a mix of externalizable and serialized java objects, in a format optimized for both performance (primarily) and for size. If the blocks of data exceed 32K, they are compressed to reduce the size – this will primarily happen with log records being sent to the log server, since most blocks are well below 100 bytes.
Sample
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Configuration
Following is a sample configuration for setting up 2 servers in a cluster – it shows which settings to change, and where to do it.
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Dynamic Loadbalancing is supported by clients connecting to config server, log server, session controller and useradmin servers. But do note that e.g. loadbalancing between multiple log servers although working perfectly can be quite a hazzle since it is impossible to predict on which log server your logging output from a particular agent will end up at.
Benefits and
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Drawbacks
It is important to recognize the benefits and the drawbacks of using dynamic loadbalancing.
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But if a server goes down or later is brought back up, then the load (measured in number of connected clients) will be shared equally between all currently available servers in a cluster.
How it
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Works
A client participating in dynamic loadbalancing is in reality connected to all available servers, and will have a single active connection and the rest will be passive. A server, e.g. config server component is not logically aware of passive connections existing at all – this is handled by the communication framework used by each server.
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When the server becomes available again, the clients will re-distribute their load across all available servers.
Example with and
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Without Dynamic Loadbalancing
You have a setup with 4 servers and 200 agents. The configuration looks like this:
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We only recommend using dynamic loadbalancing if you have a system with significant load, or a significant number of connected agents. If you only have e.g. 10 agents and 2 servers in a cluster it is usually not worth the hazzle to use dynamic loadbalancing, but if you have a system with e.g. 4 servers in a cluster and several hundred agents, then it is a very good idea to use dynamic loadbalancing.
Monitoring
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Loadbalancing
It is quite easy to monitor (and manipulate) the load distribution between servers using the Ceptor Console
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