You are looking for a way to rescan all your hosts in a cluster for new datastores, using powercli? Here is the code snippet you are looking for:
Get-Cluster ‘name_of_your_cluster‘ | Get-VMHost |
Get-VMHostStorage -RescanAllHba -RescanVmfs
With this command, all hosts in your cluster (fill in the name of your cluster…) will perform a rescan for new storage devices and new VMFS volumes.