Preferred path behaves like MRU if preferred paths are not specified in fixed path policy

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• When preferred path for a LUN is not specified by user in the fixed path policy, the system automatically chooses a fail over preferred path that behaves like a MRU
• If the system configured preferred path fails and becomes active again in an Active/Active configuration, the path remains with the other path

Environment

VMware ESX Server 3.5.x
VMware ESXi 3.5.x Embedded
VMware ESX 4.0.x
VMware ESXi 4.1.x Embedded
VMware vSphere ESXi 5.5
VMware ESXi 4.0.x Embedded
VMware ESX 4.1.x
VMware vSphere ESXi 5.1
VMware ESXi 4.0.x Installable
VMware vSphere ESXi 5.0
VMware ESXi 4.1.x Installable
VMware ESXi 3.5.x Installable

Cause

This issue occurs because the system is unable to determine the preferred or optimal path and, therefore after a fail over, the ESX host stays on the other path until it fails.

Resolution

To resolve this issue, manually set the preferred path. By choosing the preferred path manually, when the path fails and returns to active again, it returns to the configured preferred path and behaves as a fixed path.

To set the fixed path policy for Active/Active configuration, perform the following:

1. Click Configuration > Storage.
2. Right-click on the datastore, and select Properties.
3. Click Manage Paths and choose the Preferred path.