Storage Virtualization — the Next Step in Controlling Spiraling Costs
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Technical Bulletin / Coffee Break Storage virtualization — the next step in controlling spiraling costs Although hardware storage prices have come down, storage administration and software expenses can still run many times the cost of storage hardware. For many businesses, controlling these costs is crucial to lowering the total cost of ownership. Storage consolidation can provide a partial solution by expanding device connectivity and reducing points of management. However, once storage is consolidated, the job is only half done. You still need a centralized, flexible method of management that masks the complexity of the storage environment and reduces administrative overhead. That’s where virtualization fits in. Focus on the task — Not the technology Once storage is Operating system technologies have moved toward consolidated, the job is virtualization in a variety of areas, but the goal is the only half done. You still same: to make a complicated task easy to perform. need a centralized, flexible Thus, memory management has evolved from having method of management to manually assign a fixed amount of memory for that masks the complexity each application to a virtual memory subsystem that dynamically allocates memory as needed. Likewise, of the storage environment e-mail communication was once restricted to and reduces administrative individuals who could understand arcane network overhead. That’s where routing schemes. Today, you simply type the destination virtualization fits in. address; switches and routers make sure the e-mail reaches the correct server. As with memory management and e-mail, storage virtualization seeks to simplify cumbersome tasks — such as allocating storage, load Traditional Disk Storage balancing, configuring RAID, and backing up Requires the management of individual Many points of and restoring data. Optimally, the physical disks disks. Expansion and reconfiguration are management result difficult, disruptive, and manual tasks. and complex underpinnings of the storage are in more user errors concealed from administrators and servers. Management Disk space is presented to the operating system as a “logical volume” that appears to be a Virtualization normal disk or partition. With a layer of abstraction between storage Storage Virtualization Solution Provides a dynamic “pool” of storage Few points of and hosts, administrators are no longer bound that masks the underlying complexity. management mean by the physical dimensions of a disk or forced Raid configuration, load balancing, fewer user errors through complex steps to perform basic and backups are greatly simplified. storage management tasks. Not only can virtualization transparent to applications. help to improve efficiency and productivity, it can also reduce the time, effort, and knowledge needed to manage The future is here storage. As shown in the table, a storage subsystem-based product that can span arrays represents the ideal virtualization Not all solutions are created equal solution—providing a scalable “pool” of storage, in addition A key objective of virtualization is to make to technology that hides the the life of a storage administrator easier, underlying configuration, Early generation virtualization but not all solutions effectively meet does little to improve ease-of-use: regardless of its complexity. this goal. Early generation virtualization Dell is delivering such a • Increases components to manage products can provide flexibility, but product with its EqualLogic they are essentially consolidated • Only consolidates storage PS Series array, which storage solutions that do little to reduce • Tasks remain complex and obtrusive combines the best of complexity. Some can actually increase Next generation virtualization storage consolidation and the number of components to manage, helps to simplify storage virtualization in an iSCSI- and load balancing, RAID configuration, administration: based SAN. EqualLogic PS and provisioning remain difficult, manual • Decreases components to manage Series arrays are designed operations. to provide a cost-effective, • Provides pool of storage, not just disks high-performing, scalable To address these inadequacies, next • Masks complexity of tasks storage solution that can generation virtualization solutions mask • Operations are transparent to users utilize an organization’s the underlying complexity of the storage existing network infrastructure environment by providing one or more and personnel skills. This can “pools” of protected storage, not just be just what businesses need to decrease the costs—and a set of consolidated disks. Loads can be balanced and complexity—of managing storage. logical volumes created and expanded—on demand and with no user impact. RAID configuration and backup, replication, and snapshot capabilities are integrated and Virtualization method Benefits Deficiencies Host-based Supports multi-vendor storage systems. Many points of management. Single software vendor. (volume manager) Difficult to deploy, especially with mixed platforms. Must install and manage software on each host. Steals bandwidth * from host. Slow snapshot capabilities. Storage pool limited to a single host. In-band appliance Supports multi-vendor storage systems. Additional point of management. Single switch vendor (located in I/O path) Optimizes performance if a dedicated (difficult network upgrades). No knowledge of device switch. capacity or status. All I/O must flow through appliance. ** Steals bandwidth from host. Slow snapshot capabilities. Out-of-band appliance (located Supports multi-vendor storage systems. Additional point of management. Single switch vendor out of I/O patch, except for Optimizes performance. (difficult network upgrades). No knowledge of device snapshots) capacity or status. May not support all platforms. Must install software on host (or HBA). Steals bandwidth from host. ** Slow snapshot capabilities. Storage subsystem Reduces management complexity. Standard Some products limit storage pool to a single array. Single network hardware. Optimizes performance. storage vendor. **** Integrated RAID management. Fast snapshot capabilities. Can co-exist with other solutions. * Degree to which solution meets next generation virtualization criteria (4 stars is the maximum score). Simplify your Storage at www.dell.com/PSseries © 2010 Dell Inc. All Rights Reserved. CB103_USA_032607_080610.