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.