HP-UX 11i v3 Mass Storage I/O Performance Improvements

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Glossary
Async Disk Driver
The Asynchronous Disk Pseudo Driver in HP-UX, named asyncdsk in the OS, is used to perform
asynchronous I/O in a user application for improved performance. User processes or threads in
which asynchronous I/O is performed do not need to wait for the I/O to complete before going
on to do other work. Instead they are asynchronously notified of I/O completions. The Async Disk
Driver is commonly used with the Oracle database application on HP-UX.
DSF
Device Special File
HBA
Host Bus Adapter. For example, an I/O card with one or more ports on it for attachment to Fibre
Channel, parallel SCSI, or other mass storage connectivity to a device.
LUN
An end device in a mass storage interconnect.
LUN path
A path to a LUN through an HBA port and a target port. Also known as a lunpath.
Multi-pathing
The ability to find the various paths to a LUN, and failover to an alternate path when a given path
fails, or to load-balance across the various paths. HP-UX 11i v3 provides native multi-pathing,
which is built-in to the mass storage stack.
Parallel dump
A new crash dump feature in HP-UX 11i v3 that allows the dump process to be parallelized to
produce significantly reduced dump times.
Target
A storage device attachment to a mass storage interconnect such as Fibre Channel or SCSI.