A print cluster is just a group of print servers. The print cluster can host one or more spooler resources and it can also host one or more virtual print servers. Print server clusters can be used to consolidate multiple print servers, migrate a single print server to a cluster, and support one or more new print servers. Print server clusters can help reduce downtime in environments where printing is critical. Because virtual servers on a cluster appear as standard print servers to the client computer, a print spooler can be invisibly integrated into a cluster from an existing printing environment without changing the server name. Because of this ability, you can consolidate multiple print servers into a single cluster without making any changes to client computer configurations.
Printer Pooling is not used for print servers. Printer Pooling just sends a print job to multiple local or network printers and will be printed on the first available one.
