Free Trial

Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.

Share this Page URL

Types of storage virtualization > Storage virtualization models - Pg. 83

Tape virtualization Virtualization software abstracts tape drives to provide immediate response to replication seeking access. Typically, this involves the use of disks as well as tapes. 5.3.1 The IBM TotalStorage vision You can implement storage virtualization at the host, network, and storage level. The IBM vision is to move the storage device management intelligence out of the server, reducing the dependency of having to implement specialized software, like Logical Volume Managers (LVM), at the server level. By putting virtualization function in the network where it can be accessed by all connected servers and storage, organizations can avoid duplication of storage function, simplifying the environment. By implementing at a fabric level, storage control is moved into the network, which gives you the opportunity to use all storage for storage virtualization, and at the same time reduces complexity by providing a single view of storage. The storage network can be used to leverage all kinds of services across multiple storage devices, including storage virtualization. By implementing at a file system level, file details are effectively stored on the storage network instead of in individual servers and storage devices. This design means the file system intelligence is available to all application servers. Doing so provides immediate benefits: a single namespace and a single point of management. This eliminates the need to manage files on a server by server basis. 5.3.2 Storage virtualization models For storage virtualization, two models can be drawn. The two models are in-band and out-of-band . These models are not mutually exclusive. In many environments, a combination of both models may be desired. Both models have their strengths and applications. In-band virtualization In-band virtualization is sometimes called symmetric or synchronous virtualization , otherwise known as block aggregation . The in-band virtualization model is shown in Figure 5-10. Chapter 5. Storage virtualization 83