• Using the VMware vSphere Web Client 
• Using the ESXi Command Line Interface

Using the VMware vSphere Web Client 

• Log in to the vCenter web client GUI and select an ESXi host in your inventory.
• Right Click on the host and navigate to Storage > Rescan Storage 

• You would be prompted to either Scan for new Storage Device or Scan for new VMFS Volumes 

• The first option, for rescanning for new storage devices, shall rescan all available adapters to look for any new devices that have been detected (or retire devices that are no longer in use - as part of a cleanup)
• The second option, for recanning for an new VMFS volumes, all rescan all the detected devices for a VMFS backed volume (datastore). 
• You could select either both of the options at the same time or you could run these tasks individually. 
• Monitor the progress of the rescan task in the Work In Progress tab on the right or from the ESX/ESXi host console in the /var/log/vmkernel.log  and /var/log/vobd.log log files. 

Using the ESXi Command Line Interface

1. Log in to the ESXi host console. 
2. To rescan, run one of these commands:
   • To rescan a specific HBA

Where <vmkernel SCSI adapter name> is the vmhba# to be rescanned.

Example:

# esxcli storage core adapter rescan -A vmhba3 | --adapter=vmhba3
 

• To rescan all HBA's 

Note: 
To get a list of all adapters, run the either of the following commands : 

esxcfg-scsidevs -a
or
esxcli storage core adapter list 

3. To search for new VMFS datastores, run this command: