HP LeftHand SAN Solutions Support Document - Application Notes - Best Practices for Enabling Microsoft Windows with SAN/iQ®
Table Of Contents
- Application Notes Best Practices for Enabling Microsoft Windows with SANiQ
- Contents
- 1 Chapter: Enabling LeftHand SAN volumes with the Microsoft™ iSCSI 2.0x Initiator
- 2 Chapter: Finding the iSCSI Initiator Version
- 3 Chapter: LeftHand Networks and Microsoft™ MPIO Support
- 4 Chapter: Expanding a Windows Volume on the SAN
- 5 Chapter: Shrinking a Windows Volume on the SAN
- 6 Chapter: Setting the Windows Disk Partition Offset for Optimal Performance
- 7 Chapter: Ensure That Application Resources on iSCSI Volumes Come Online After a Server Reboot
- 8 Chapter: Microsoft™ iSCSI Initiator Session Timeout Setting
- 9 Chapter: Measuring Performance in a Windows Environment
- Overview
- Using Windows Performance Monitor to Measure SAN Performance
- Setting up Windows Performance Monitor
- Saving a Performance Monitor Log for Analysis
- Monitoring More Than One Server Simultaneously
- Scheduling Performance Data Collection
- Using IOMeter as a SAN Benchmark Tool
- Configuring the ISCSI Volume
- Configuring IOMeter
- Configuring IOMeter Access Specification for each Test
- Running the Test
- Interpreting Results
- Access Specifications to Run
- 10 Chapter: Frequently Asked Questions
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8 Chapter: Microsoft™ iSCSI Initiator
Session Timeout Setting
Overview
This section describes the LeftHand Networks recommended setting for the
iSCSI initiator session failover timeout setting, which is governed by the
MaxRequestHoldTime registry parameter.
Important Note: With SAN/iQ 6.6.x or earlier, or with any version of
SAN/iQ when the LeftHand DSM for MPIO is not being used, if the
Microsoft™ DSM is installed during the iSCSI initiator setup, a
separate 30 second iSCSI failover timeout is used instead of the
MaxRequestHoldTime value, which is ignored. This 30 second timeout
value can have adverse affects on iSCSI volume and data availability
(see below). Therefore it is critical to uninstall the Microsoft™ DSM in
these situations. See section 3 for details on uninstalling the
Microsoft™ DSM.
Background
The Microsoft™ iSCSI Initiator session failover timeout is set to 60 seconds by
default. This default timeout period is generally too short to accommodate all
iSCSI failover delays that may occur. For example, iSCSI failover events and
associated delays can be triggered by storage module reboots/upgrades,
network outages, power outages, etc. If the iSCSI session failover time exceeds
the timeout period, the Initiator can go into a reconnect state, resulting in
potential loss of connectivity for any pending I/O operations, resulting in those
I/Os being flushed from the server cache.
To prevent this reconnect state from happening, the Initiator timeout value
should be increased on every system that has an iSCSI volume. LeftHand
Networks recommends that this timeout value be set to 10 minutes
(600 seconds).