* VMWare uses this as the root of their vSAN technology. * Nimble and other storage appliance manufacturers use a bank of SSDs to cache frequently-read data, a

* VMWare uses this as the root of their vSAN technology. * Nimble and other storage appliance manufacturers use a bank of SSDs to cache frequently-read data, and have layers of fast- and slow-HDDs to store data relative to its access frequency. * Hybrid HDDs have been around for years.