HP PCIe U320, User Manual

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Increase transfer size
If you are writing to an application that uses a lot of sequential disk I/O to a contiguous area on disk,
you should use as large a transfer size as possible to reduce overhead on the system, on the SCSI bus
and within disk drives.
Analyze your I/Os
For large sequential data transfers, use Direct I/O by selecting
FILE_FLAG_WRITE_THROUGH
and
FILE_FLAG_NO_BUFFERING
fl ags with your
CreateFile
call to avoid the overhead of copying data
from one area of memory to another, to reduce the number of SCSI commands that must be executed,
and to leave system pages available for other data.
If your application requires a small number of I/Os and the transfers are rather small, however, you may
get better performance by letting the system cache your data in the system pages.
You might want to use over-lapped I/O using the
FILE_FLAG_OVERLAPPED
option with the
CreateFile
call. Overlapped I/O allows the application to send many commands to the device at
once.
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Troubleshooting