What is SAN virtualization?

A SAN is essentially a local area network (LAN) that is interconnects remote data storage devices, such as disk arrays, optical jukeboxes, and tape libraries, to a server array. SANs are frequently used to manage transactional data that require fast, block-level access to hard drives. Such hard drives might include databases, email servers, or high-usage file servers.

Storage virtualization is a process by which logical storage (virtual storage) is abstracted away from physical storage (hardware storage). Physical storage is combined into storage pools and then the logical storage is generated from that. The goal of virtualization in a SAN is to virtualize many disk arrays scattered across a network with vendor-specific dependencies, into essentially one storage device with consolidated management functionality.

Various solutions can be implemented in a disk array to present users with a logical space to transparently manage and map logical disks (also called “vdisks”) on top of actual physical hardware locations. Logical storage can then be mapped to any piece of physical storage without regard for certain underlying incompatibilities. There is also greater flexibility and mobility in a virtualized storage environment, where much of the complexity is hidden.

Benefits
The benefits of SAN virtualization are similar to the benefits of your basic SAN, but with the added flexibility of virtualization. SANs consolidate private storage space into disk arrays using multiple servers, enabling higher storage capacity. The shared storage provided by a SAN also simplifies data mobility and management. Virtualized resources make this process even simpler and more flexible because resource management is unified across multiple storage devices.

In virtualized SAN environments, organizations can easily provision, grow, and move data according to your business requirements. Because a variety of disparate storage devices can all be consolidated into one pool, some companies will be able to use every bit of the infrastructure they’ve invested in, even the devices that have been stranded and separated from the whole because of incompatible technology. Operations can be simplified when all of the virtualized devices begin using a consistent set of data services. By provisioning the right types of storage to match each set of data, you can optimize your storage costs as well.

SANs are very effective during disaster recovery because servers can boot from the SAN itself, therefore faulty servers can be quickly replaced. Virtualized storage gives you the ability to take low-capacity snapshots and re-apply them whenever data is lost or you just want to go back to a certain state.