HP StorageWorks Auto Path VA Software - Manual (Page 5)

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1 PRODUCT DESCRIPTION
Overview
Congratulations on your purchase of the HP SureStore Auto Path Virtual Array (Auto Path VA)
product. This software product provides automatic input/output (I/O) path failover and load balancing
for servers configured with multiple host bus adapters connected to HP SureStore Virtual Arrays.
Typically, system disk I/O is sent directly to the Windows disk driver. Auto Path VA is a filter driver
that fits between the Windows disk driver and the host bus adapter driver. Auto Path VA, which is
transparent to all applications, provides these features:
• Enhanced data availability.
• Dynamic load balancing over multiple paths.
• Automatic path failover and recovery to an alternate path.
• A graphical user interface and a command-line user interface.
Dynamic Load Balancing
Auto Path VA performs dynamic load balancing of data flow through multiple paths. It detects multiple
paths to each device (or LUN) and allocates the data load among the paths for optimum performance.
This multipath load balancing prevents any path from becoming overloaded and helps prevent the
congestion that occurs when many I/O operations are directed to common devices along the same path.
Load balancing is performed using a policy selected by the administrator.
If a preferred path is specified for a device, the entire I/O for that particular device flows through the
preferred path. No load balancing is done by Auto Path VA.