Distributed Data Synchronization (DSync)
Clusters
NAS Clusters
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Set of NAS
that share a single source for session and state data
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Session
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A continuous
series of interactions between a user and a Netscape Application
Server application. The term session is widely used
to refer to a Web browser session, but with NAS, session
refers more specifically to a series of user interactions that are
tracked by a Netscape Application Server application. The user's
session with a Web browser or other client software might start
before the NAS application begins tracking the user, and could continue
after the application stops tracking the user.
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State
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A distributed
data storage mechanism for storing the state of a collection of
application variables whose scope is global within the application.
Information in the state layer can be organized in a hierarchical
structure, or tree.
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High Availability
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Because
state and session information is stored and retrieved from from a
single server in a cluster, new requests can execute on any server
in the cluster. |
Failover
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By eliminating
single points of failure, Netscape Application Server offers maximum
application availability. Distributed state and session management
prevent loss of user or application data if a failure occurs. (Instances
of requests may be lost at the time of failure, but the session
and application will persist).
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High Scalability
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Application
scaling can be performed either by adding more servers to a cluster
of servers or by adding more CPUs to a multi-CPU system.
Application
components can then be deployed to the new servers. Developers do
not need to change any application logic as the deployment base
grows.
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