Production workload is maxing out storage and can not expand

Products

• VMware vSphere ESXi

Issue/Introduction

Attempting to add additional storage fails. 
When attempting to do a storage scan from CLI there is the following:

esxcli storage core adapter rescan --all 
Error when rescanning adapter vmhbaX. Error was Unable to scan VMkernel SCSI subsystem for new device. Unable to complete Sysinfo operations. Please see the VMkernel log file for more details.: Maxium allowed SCSI paths have already been claimed. Please see VMkernel log for more information

Environment

ESXI (all) 

Cause

This is an expected behavior as total path to the host has reached upper limit.

The following command will provide the number of paths currently in use

esxcfg-mpath -b | grep -v naa.* | wc -l

Number of total paths on a server has an upper limit of 4096 (Fiber Channel)

Resolution

Down size the path to ESXi host by decommission devices which is no longer required/needed or reduce the number of redundant paths. 

Additional Information

Newly added LUNs are not visible on the cluster/Host