There are two major types of virtual tape architectures: bundled appliances that include virtualization software and disk storage, and virtual tape software that runs on a server platform with a variety of back-end storage devices. An appliance provides higher levels of integration and reduces the operational complexity of deployment and administration. A software-only approach offers more flexibility and investment protection because it enables storage administrators to leverage their existing server and storage infrastructure to deploy virtual tape. In general, an appliance may be more appropriate for small- to medium-sized businesses, while a software-only approach fits best with the operational practices of enterprise-sized organizations.
Examples of appliances include Pathlight VX from Advanced Digital Information Corp. (ADIC), Revolution 200T from Copan Systems, Clariion Disk Library from EMC Corp., DX100 from Quantum Corp., Sepaton S2100-ES from Sepaton Inc. and the Spectra RXT from Spectra Logic. Software products include Securitus from Alacritus Software Inc., VTF Open from Diligent Technologies Corp., VirtualTape Library from FalconStor Software and Virtual Storage Engine (VSE2) from Neartek.
A virtual tape solution manages two sets of data elements: source data and control data. Source data refers to the data being backed up, while control data consists of the mapping between virtual and physical resources and policy parameters. The logical or physical separation of data and control paths improves performance and scalability. Storage managers should look for products that can scale data paths independent of control paths.
