Rescan all disks in a cluster
If you're adding storage to an existing cluster, you've probably found yourself logging onto each node and running diskpart to rescan volumes. You may even have had a dozen RDP sessions open, one per node, in which you can just hit Up Arrow to run rescan again. For what seems like the hundredth time.
Stop it! PowerShell and Remoting to the rescue with this one liner:
Get-Cluster CLUSNAME | Get-ClusterNode | % { Update-HostStorageCache -Cimsession $_.Name }