Spilling and throttling, Availability – HP e-Commerce Server Accelerator sa7120 User Manual

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C H A P T E R 3

Multiple SA7100/SA7120s and Cascading Processing

15

Spilling and
Throttling

When the SA7100/SA7120’s “spill” option is enabled, if a given
SA7100/SA7120 cannot process a request within a specified interval,
the request is passed on, still encrypted, to the next SA7100/SA7120
in line. The last SA7100/SA7120 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 SA7100/SA7120
“throttles,” that is, will not accept incoming requests when it becomes
overloaded.

Cascaded SA7100/SA7120s

Availability

When a SA7100/SA7120 fails or is set to Bypass mode while Fail-
through is enabled, the SA7100/SA7120’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. In installations
with multiple SA7100/SA7120s, the next unit in the cascade picks up
the encryption/decryption workload, while in single SA7100/SA7120
configurations, the server assumes the load. See “Failure/Bypass
Modes” in Appendix B for more information.

HP e-Commerce Server Accelerator SA7100/7120s

Hub/Router/Switch

Server

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