iSCSI rescan takes longer time than expected when using port binding with a single VMNIC

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• You are port binding the same vmknic on two different subnets to access a iSCSI LUN, and the rescan takes longer than expected to complete.
• The /var/log/vmkiscsid.log file (ESX host) or /var/log/messages log file (ESXi) contains an error similar to:
  
  Reason: 00080000 (Initiator Connection Failure)

Environment

VMware ESXi 4.1.x Installable
VMware ESX 4.0.x
VMware ESXi 4.0.x Installable
VMware ESXi 4.1.x Embedded
VMware ESXi 4.0.x Embedded
VMware ESX 4.1.x

Resolution

This is expected behavior in this configuration. When using port binding, the iSCSI Initiator tries to open a full-mesh configuration and attempts to open a connection from each vmknic to each array address, which may result with a few connection failures causing rescan to take a while.

Notes:

• This issue affects only the rescan time and does not affect the post-rescan performance.
• As a rescan occurs during ESX/ESXi host boot, host start-up time can be affected.

Additional Information

Considerations for using software iSCSI port binding in ESX/ESXi