Expand Configuration and Management Manual (H06.03+)

Configuring Expand-Over-ServerNet Lines

Expand Configuration and Management Manual—529522-002

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ServerNet Cluster Monitor Process ($ZZSCL)

The ServerNet cluster monitor process, $ZZSCL, monitors and responds to events

relevant to ServerNet cluster operations and is responsible for discovering and

managing the cluster.

The ServerNet cluster monitor process is not limited to a particular processor pair; it

can migrate within a user-specified set. A member of a ServerNet cluster monitor

process pair can go down without its processor going down. If both primary and

backup processes fail, the ServerNet monitor may be absent for a short period, until

the persistence manager starts a new ServerNet cluster monitor process. Since data

traffic does not involve the ServerNet monitor, it could continue during this time.

$ZZSCL must be configured and started before the Expand-over-ServerNet

line-handler processes can be started. For information about configuring $ZZSCL, refer

to the ServerNet Cluster Manual.

ServerNet Cluster Product

ServerNet clusters enable multiple Integrity NonStop NS-series servers to work

together and appear to client applications as one large processing entity. ServerNet

clusters extend the ServerNet X and Y fabrics outside the system boundary and allow

the ServerNet protocol to be used for intersystem messaging. For more information on

the ServerNet Cluster product, refer to the ServerNet Cluster Manual.

Wide Area Network (WAN) Subsystem

You create an Expand-over-ServerNet line-handler process by adding it as a device to

the WAN subsystem. For each node in a ServerNet cluster, you must create one

Expand-over-ServerNet line-handler process for every other node in the cluster. The

WAN subsystem is preconfigured and started during the system load sequence. For

information about the WAN subsystem, refer to the WAN Subsystem Configuration and

Management Manual.

X and Y Fabrics

X and Y fabrics are a collection of connected routers and ServerNet links that,

together, provide an interconnection for Integrity NonStop NS-series servers. Each

processor connects to both fabrics. The X fabric and the Y fabric are not connected to

each other; therefore, a ServerNet packet cannot cross from one fabric to the other

and a failure in one fabric does not affect the other fabric.