EMC QLogic - Manual (Page 39)

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Introduction 3-3
Configuring an EMC Boot Device
◆ Storage Area Network service/upgrade procedures, such as
firmware upgrades or hardware replacements
EMC recommends moving the Windows virtual memory paging file to a
local disk when booting from the storage array. Consult your Windows
manual for instructions on how to move the paging file.
How to Determine I/O Latency and Load on the Boot LUN
The current restrictions for boot-from-array configurations listed in
the EMC Support Matrix represent the maximum configuration that is
allowed using typical configurations. There are cases where your
applications, host, array, or SAN may already be utilized to a point
when these maximum values may not be achieved. Under these
conditions, you may wish to reduce the configuration from the
maximums listed in the EMC Support Matrix for improved
performance and functionality.
Here are some general measurements than can be used to determine
if your environment may not support the maximum allowed
boot-from-array configurations:
◆ Using the Windows Performance Monitor, capture and analyze
the Physical Disk and Paging File counters for your boot LUN. (For
Windows NT 4.0, you might have to enable disk performance
counters manually; refer to Microsoft support for the description
and use of the Windows Performance Monitor.) If response time
(sec/operation), or disk queue depth seem to be increasing over
time, you should review any additional loading that may be
affecting the boot LUN performance (HBA/SAN saturation,
failovers, ISL usage, and so forth).
◆ Use available Array Performance Management tools to determine
that the array configuration, LUN configuration and access is
configured optimally for each host.
Possible ways to reduce the load on the boot LUN include:
◆ Move application data away from the boot LUN.
◆ Reduce the number of LUNs bound to the same physical disks.
◆ Select an improved performance RAID type.
◆ Contact your EMC support representative for additional
information.
QLogic_Windows.book Page 3 Thursday, March 10, 2005 10:31 AM