Dell Storage with Microsoft Storage Spaces Best Practices Guide

Configuring Multipath I/O (MPIO) on each server enables Windows Server to use alternate paths to hard disk drive in the event of a failure and provides load balancing. When properly cabled and when using dual-port SAS physical disk drives, each server has two physical paths to each physical disk drive.

The recommended global MPIO load balancing policy for this solution is Fail Over Only (FOO).

Run the following PowerShell command on each server to enable FOO:

Set-MSDSMGlobalDefaultLoadBalancePolicy -Policy FOO 

This sets the global value to FOO. Any new drive added to the solution will be automatically configured as FOO. Dell recommends you to use Round Robin for SSDs and Fail Over Only for HDD for optimal performance in most applications.

To configure a different load balance policy for different groups of drives use the following code. Dell uses the drive model identifier to make quicker changes. If you have a mix of models of HDDs and SSDs you may have to go through and change them manually.

Run the following command to get the Target Hardware Identifier value:

mpclaim -e

mpclaim -l -t "Target H/W Identifier" Policy Number

Policy Number options:

0 = Clear the Policy

1 = Fail-Over Only

2 = Round Robin

6 = Least Blocks

You must run the process for HDD and SSDs. There are other policy number options available but these are the only ones that Dell supports.

If a pool is already created, you must manually acquire the drive Hardware Identifier and set a policy for it.