Failover mode changes from 4 to 1 automatically with EMC storage arrays on ESXi/ESX

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:
When connecting an ESXi/ESX host to EMC storage arrays such as the VNX, you may experience these symptoms:

• The failover mode on the array itself changes from 4 (ALUA) to 1 (Active/Passive) automatically for the affected hosts
• Hosts lose access to storage presented from the storage array
• A reboot of the hosts does not detect storage presented with an ALUA Storage Array Type Plugin (SATP) as expected.

Environment

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

Cause

This issue can be caused by one of these conditions:

• Not presenting a data LUN with a LUN ID = 0 to the host(s)
• Having a combination of a data LUN with a LUN ID = 0 and a management/LUNZ device presented to the host(s)

Resolution

When an ESXi/ESX host detects a management/LUNZ LUN, and then a data LUN with a LUN ID = 0 is presented to the host(s), you must perform a rescan of the storage adapters on the ESX host twice. The first rescan deletes the management/LUNZ device from the ESXi/ESX host, and the second rescan detects the real host LUN 0.

This is a known issue with some EMC storage arrays and is documented in EMC Primus ID emc292282.

Note: The preceding link was correct as of June 17, 2014. If you find the link is broken, provide feedback and a VMware employee will update the link.

Note: You may need an EMC Primus account to access EMC articles.

This issue is resolved in ESXi 5.x with Flare 30 and later.