Multiple Sa7150S And Cascading; Scalability And Cascading; Spilling And Throttling; Availability - HP P4518A - Traffic Management Server Sa7150 User Manual

C H A P T E R 3
Multiple
SA7150s and
Cascading
HP e-Commerce/XML Server
Accelerator SA7150
Router
NOTE: The SA7150
restarts when spill is
enabled. Depending on
the size of the current
configuration file, it can
require from 30 seconds
to seven minutes to return
to operations.
32
HP e-Commerce/XML Server Accelerator SA7150 User Guide

Scalability and Cascading

The SA7150's capabilities are scalable by chaining, or "cascading,"
multiple SA7150s together. In such configurations, each unit's server
side connector is wired to the network side connector of the next
SA7150 in line. The last SA7150 in line is connected to the server or
switch.
HP e-Commerce/XML Server
Accelerator SA7150
Cascaded SA7150s

Spilling and Throttling

When the SA7150's "spill" option is enabled, if a given SA7150
cannot process a request within a specified interval, the request is
passed on to the next SA7150 in line. The last SA7150 on the server
side can also be enabled to spill to the server. Spilling is performed
dynamically on a connection-by-connection basis. (See spill
command, Chapter 5, "Command Reference.") If spill is disabled, the
SA7150 "throttles," that is, does not accept incoming requests when
it becomes overloaded.

Availability

When a SA7150 fails or is set to Bypass mode while Fail-through is
enabled, the SA7150's network side and server side network adapters
are directly connected, allowing traffic to pass through to the next
device until the failed unit is brought back into service. This feature
eliminates a single point of failure and provides a high level of
availability, should there be a failure. See "Failure/Bypass Modes" in
Appendix B for more information.
XML Server 1
XML Server 2
hub/switch
XML Server 3