Least queue depth with subset, Least path weight with subset, Changing load balance policies on the – Dell PowerVault MD3220i User Manual

Page 78: Windows server 2008 operating system

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Appendix—Load Balancing

Least Queue Depth With Subset

The least queue depth with subset policy is also known as the least I/Os or

least requests policy. This policy routes the next I/O request to a data path

that has the least outstanding I/O requests queued. For this policy, an I/O

request is simply a command in the queue. The type of command or the

number of blocks that are associated with the command are not considered.
The least queue depth with subset policy treats large block requests and small

block requests equally. The data path selected is one of the paths in the path

group of the RAID controller module that owns the virtual disk.

Least Path Weight With Subset

The least path weight with subset policy assigns a weight factor to each data

path to a virtual disk. An I/O request is routed to the path with the lowest

weight value to the RAID controller module that owns the virtual disk. If

more than one data path to the virtual disk has the same weight value, the

round-robin with subset path selection policy is used to route I/O requests

between the paths with the same weight value. The least path weight with

subset load balance policy is not supported on Linux operating systems.

Changing Load Balance Policies on the Windows Server 2008 Operating

System

Load balancing with the MD3200i series storage array is only available for

Windows Server 2008 and later versions of the operating system. You can

change the load balance policies from the default round robin with subset by

using either the:

• Device manager
• Disk management

To change the load balance policy using Windows Server 2008 device manager:

1 From the desktop of the host, right-click My Computer and select

Manage to open the Computer Management dialog.

2 Click Device Manager to show the list of devices attached to the host.
3 Right-click on the multi-path disk device for which you want to set the

load balance policies, then select

Properties.

4 From the MPIO tab, select the load balance policy that you want to set for

this disk device.

book.book Page 78 Sunday, September 11, 2011 10:24 PM

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