Benefits of Virtualized Storage Infrastructure
Storage systems in the past have typically been a combination of hardware and software components along with disk drivers, and have provided rapid and reliable storage capacity for computing and data processing. Today storage virtualization offers a more flexible and scalable option as it separates the storage-management software from the foundational hardware infrastructure. Storage virtualization is employed as a technique to abstract information about all of the storage hardware resources on storage area networks (SANs). For IT-intensive firms looking to cut back on the time and resources spent on managing multiple storage devices, the answer lies in the storage virtualization technology for data storage management. In addition to providing increased storage utilization and the ability to add or delete storage without having an impact on the application’s availability, storage virtualization technologies also support non-disruptive data migration.
Types of Storage Virtualization
With the promise of simplified management, optimized cost structures, and data protection, storage virtualization solutions combine distributed access with centralized control to provide both centralized and distributed storage. Although numerous technologies implemented across enterprises qualify to be included under the umbrella term of storage virtualization, a common denominator to these solutions is the abstraction layer used by them to cloak the underlying physical storage. Based on this, storage virtualization has been classified into three major types.
1. Host-based Storage Virtualization
Implemented through a logical volume management (LVM) application that is installed on each server, host-based virtualization conceals the complexity of physical storage, while offering a logical view of storage resources to the operating system. As the abstraction of physical storage takes place within the server itself, there is no splitting of control and data paths. Although the host can be multi-pathed to shared storage with a varied mix of storage target devices, the virtualization on each host has to be manually configured and managed separately.
2. Fibre Channel Storage Virtualization
Preferred for exceptional levels of storage networking performance and security, Fibre Channel storage networking technology is considered a conventional approach to storage area networks (SANs) for virtualization storage networking. In addition to providing a high-bandwidth and low-latency storage network to handle aggregated storage traffic, fiber channel SAN offers features such as live migration.
3. Block-level Storage Virtualization
A key advantage of implementing a block-level storage virtualization solution is that it provides a flexible and logical arrangement of storage capacity to applications and users while efficiently concealing its physical location. The block-level storage virtualization functions as a software layer that intercepts I/O requests to logical capacities and then maps them to the appropriate physical locations.
Complications Associated with Virtual Storage
The complexity of storage virtualization projects make it imperative for businesses to consult professionals or specialist technology vendors before implementing one. For instance, IBM's SVC, a popular storage virtualization product is usually installed in pairs in an active-active configuration, in accordance with the general best practices to ensure there is no single point of failure. But for enterprises keen on using IBM SVC with their existing storage, they end up investing significantly on configuring their back-end storage devices.
The challenges associated with storage virtualization dwell around the idea that virtualization cannot be considered as a stand-alone technology but should function as a part of an existing technology environment. The inclusion of multiple vendor technologies such as switch and storage arrays further complicates the environment with interoperability issues and requires multiple management tools. Often enterprises try to ease these complexities by consolidating numerous virtualization products from a single vendor. The introduction of a virtual solution minimizes the need to standardize on a single vendor. The introduction of virtualization devices demarcates the end-to-end view into three distinct areas: the server to the virtualization device, the virtualization device to the physical storage, and the virtualization device itself. A virtualized storage environment plays a key role in ensuring that it meets all the challenges and seamlessly integrates with existing management tools to facilitate an end-to-end storage environment.