Avago Technologies LSI SAS 3041E-R - Manual (Page 39)

Windows Server 2003 Drivers 2-17
Version 1.3 Copyright © 2001, 2002, 2007 by LSI Logic Corporation. All rights reserved.
The system copies the driver to the system disk. For any adapter
other than the boot adapter, the updated driver becomes active
immediately. For the boot adapter, a message box appears indicating
that you must reboot your system for the new driver to take effect.
16. Click Finish to complete the driver upgrade.
2.3.6 Performance Tuning for Windows Server 2003
Windows Server 2003 has registry entries that you can use to tune the
performance of SCSI I/O for certain configurations. The tunable
parameter for
LSI_xxx.SYS is a guaranteed number of concurrent I/Os
for a particular SCSI bus.
The LSI_SCSI.SYS , LSI_FC.SYS , and LSI_SAS.SYS drivers are
configured by default to provide optimum performance in most standard
computer systems. Some nonstandard systems require fine tuning to
obtain peak system memory utilization and performance. If you observe
less than the advertised functionality and performance on any platform
after installation, contact LSI Technical Support. Go to the LSI technical
support home page at:
http://www.lsi.com/support/index.html#hotline
and call the listed number for assistance. LSI can provide additional
registry settings to customize the driver for specific systems and
applications.
2.3.6.1 Maximum Number of Concurrent I/Os (Guaranteed)
Windows Server 2003 guarantees a maximum of 32 concurrent I/Os
active on a particular SCSI bus. However, due to the method of memory
allocation, the actual limit of concurrent I/Os can vary greatly between
different drivers or versions of drivers. This can have a large impact on
performance benchmarking between different driver versions or adapter
vendors. In effect, one adapter may actually be able to have 70 or 80
I/Os outstanding, while another adapter could only have 32. This can
also affect systems with high performance storage subsystems, such as
disk arrays.
To enable the best performance, the driver installation process adds a
registry entry to support 255 concurrent I/Os. If you want a different
maximum value, you can use the
mpi100io.reg file to add a registry