HP StorageWorks Enterprise File Services WAN Accelerator 2.1 Installation and Configuration Guide (November 2005)

HP STORAGEWORKS EFS WAN ACCELERATOR INSTALLATION AND CONFIGURATION GUIDE 15
1 - OVERVIEW OF THE HP EFS
WAN A
CCELERATOR
If there is a serious problem with the HP EFS WAN Accelerator, it goes into
bypass mode to prevent a single point of failure. If the HP EFS WAN
Accelerator is in bypass mode, you are notified in the following ways:
 The Intercept/Bypass status light on the bypass interface is triggered. For
detailed information about bypass card status lights, see Appendix A,
“Status Lights, Technical Specifications, and Regulatory Information.”
 The Welcome page of the Management Console displays Critical in the
Status bar.
 Simple Network Management Protocol (SNMP) traps are sent.
 The event is logged to system logs (syslog).
 Email notifications are sent (if you have set this option).
When the fault is corrected, new connections that are made receive
optimization; however, connections made during the fault are not. To force all
connections to be optimized, enable the kickoff feature. Generally, connections
are short lived and kickoff is not necessary. Kickoff is suitable for very
challenging remote environments. For detailed information about enabling
the kickoff feature, see the HP Enterprise File Services WAN Accelerator
Management Console User Guide.
When the HP EFS WAN Accelerator is in bypass mode the traffic passes
through uninterrupted. Traffic that was optimized might be interrupted,
depending on the behavior of the application-layer protocols. When
connections are restored, they succeed, although without optimization.
In an out-of-path deployment, if the HP EFS WAN Accelerator fails, the first
connection from the client fails. After detecting that the HP EFS WAN
Accelerator is not functioning, an HP EFS WAN Accelerator ping channel is
setup from the client-side HP EFS WAN Accelerator to the server-side HP EFS
WAN Accelerator. Subsequent connections are passed through unoptimized.
When the HP EFS WAN Accelerator ping succeeds, processing is restored and
subsequent connections are intercepted and optimized.
New Features
The following section describes the new features in the HP EFS WAN
Accelerator.
The following features are available with Version 2.1:
 Serial Clustering. You can provide increased optimization capacity by
deploying several HP EFS WAN Accelerators back-to-back in an in-path
configuration to create a serial cluster. Serial clustering operates in a spill-
over mode where TCP connections beyond the limit of the first HP EFS
WAN Accelerator in the cluster are automatically handled by the next HP
EFS WAN Accelerator in a cluster. If one HP EFS WAN Accelerator fails,
the other HP EFS WAN Accelerators automatically take over.