By submitting your email address, you agree to receive emails regarding relevant topic offers from TechTarget and its partners. You can withdraw your consent at any time. Contact TechTarget at 275 Grove Street, Newton, MA.
There are three major types of virtualisation engine: server-based, fabric-based and array-based. Each abstracts the storage at a different level: on the server, fabric or array.
Processing is performed locally on the host system using a management console to enforce policies.
Advantages: Tends to be very scalable.
Disadvantages: Does not usually offer advanced data movement features, such as mirroring and replication.
Examples: Sun's ZFS or Veritas Volume Manager.
Processing is performed within the storage network, using one or more appliances to enforce data access and storage policies.
Advantages: Many options available, from in- or out-of-band appliances, stand alone boxes or switch-based appliances.
Disadvantages: Some in-band appliances may struggle to scale in some environments.
Examples: IBM's San Volume Controller, Network Appliances gFiler, or the Cisco switch-based Storage Services Module.
A recent twist on the fabric-based manager is to move all storage administration functions into one huge storage subsystem, and in theory it should be possible to link multiple storage controllers together in a storage pool of almost infinite capacity. Control in this model may reside either on a server running a policy management utility or the storage subsystem itself.
Advantages: There is only one point of control through which every I/O request must pass.
Disadvantages: Potentially a single point of failure. No supplier encapsulates all of their competitors' installed arrays, so this model will be the hardest to implement in a mixed-supplier shop.
Examples: Hitachi's Tagmastore, StorageTek's Iceberg and 3PAR's Utility Storage array.