Storage Virtualization: Closing the Data Management Gap
 Data is growing faster than the deployment of storage management capacity. In 2006, about 40 terabytes of disk were attached to the average non-mainframe server. The average storage administrator can handle about 8 terabytes of data. The gap between data volume and storage capacity continues to widen in the non-mainframe datacenter, even though the industry is taking every measure possible to close it.
This article, the third in a series on virtualization, covers storage virtualization. Click to read Part 1 on server-oriented containment and virtualization with a focus on Solaris Containers technology, and Part 2 on storage virtualization technology on the x64 platform.
Storage Virtualization: Reducing the Data Volume/Capacity Gap
Storage virtualization can reduce the gap between data volumes and storage capacity by consolidating multiple systems under a single interface, as well as streamlining the management of storage. In addition, virtual tape libraries can greatly improve the efficiency and effectiveness of backup operations. In a survey conducted by The Enterprise Storage Group (ESG) in October 2005, users were asked to quantify the benefits of virtualization. According to this study, storage virtualization:
- Improves device utilization levels
- Reduces storage management complexity and overall costs
- Facilitates interoperability and more "open" storage systems
- Enables resource consolidation
- Enables applications to more fully leverage virtualized storage, thanks to the tight integration of operating systems and virtualization technology
Virtualization means simplification. Anywhere an organization can begin to simplify, it should take
steps to do so immediately.
The Three Primary Tiers of the Tiered Storage Hierarchy
The industry has coalesced on a three-tiered storage model. There are multiple tiers within each of the major tiers. Primary storage, or "tier-1 storage," is the home for mission-critical, high performance online transaction processing.
Secondary, or "tier-2 storage," has been fueled by the rapid progress and movement of Serial ATA disk from the desktop into the datacenter. This has set up a very effective backup and recovery tier for data, and has become a home for a variety of different architectures that use Serial ATA disks.
Long-term data retention, or "tier-3 storage," is served by traditional tape technology, thanks to the increasing need to keep data once it has been created. When the tape library was introduced in 1988, it was assumed that most data would not have a useful life of more than two years. However, issues of regulatory compliance and fixed content have required organizations to implement long-term storage solutions to maintain data indefinitely. Tape technology dominates the tier-3 world, while disks are taking over most of the tier-1 and tier-2 applications.
Click for larger view. The graphic illustrates how data is managed and exchanged across the three-tier storage model.
A Future Storage Network Topology
A virtualized storage environment would allow data to move between different tiers without having to be read into and written from each individual server, which is often the case today. This approach provides more intelligence into the storage switching fabric and the storage devices, which can be accomplished in-band or out-of-band. This strategy implies that some of the virtualization will move away from the server and closer to the data itself for both file and block data.
Looking ahead, this or a similar architecture is likely to exist in any organization's future. Keep this in mind when talking to suppliers about what they can do to prevent the need for having every piece of virtualization architecture implemented on every single server.
Policy-Based Migration Using Sun StorageTek Products
Policy-based migration in architecture is important because it moves data between the tiers with
virtualization products. Sun StorageTek Storage Archive Manager (SAM) software provides sophisticated capabilities for defining automated archiving policies, enabling administrators to group related files into common archive sets based on attributes such as file size, ownership, or file extension, providing fine-grained control over how and where data is archived.
It also allows them to specify files that should never be archived such as temporary files, thus saving time and resources. SAM software's automated policies can use a combination of criteria to identify files that are eligible to be migrated to tape or less expensive storage. SAM software functions to virtualize the file system so that infrequently used data can be stored on less expensive media, but can be accessed as easily as if it were online.
|
The end result is better utilization of storage resources, improved management efficiencies, and lower cost.
|
|
Block data can also be migrated across tiers using Sun StorageTek 9900 Tiered Storage Manager (TSM) in conjunction with StorageTek 9900 Universal Volume Manager (UVM). UVM allows storage administrators to aggregate multiple storage systems of various type (fibre channel, SATA) from various vendors under a single management interface while providing a common set of copy and replication services.
Once the systems are aggregated into a common pool, administrators can use TSM to migrate data volumes from tier to tier according to policy. Again, the end result is better utilization of storage resources, improved management efficiencies, and lower cost.
How to Get Started in a Heterogeneous Environment
The goal is to get as many pieces of virtualization in place to reduce the storage management gap atop a common and simplified architecture. Only Sun has the expertise, broad portfolio of superior products, and the partner relationships to create scalable, end-to-end storage virtualization solutions that meet the specific needs of companies of all sizes.
- Virtual Tape: Sun provides both mainframe and open systems storage virtualization solutions. Sun StorageTek pioneered virtual tape and supports 69 percent of the mainframe virtual market with Virtual Storage Manager, and supports the open systems market with Virtual Tape Library (VTL) and disk-to-disk-to-tape solutions.
A tape virtualization solution from Sun reduces complexity in growing data environments. It simplifies IT management tasks, allowing data managers to more easily interact with a disparate collection of systems, solutions, processes, and interfaces.
- Disk System Virtualization: Sun is the only provider of both mid-range and enterprise class disk virtualization solutions. These solutions allow organizations to aggregate multiple storage systems from various vendors under a single point of control, and provide them with a common set of management tools and copy/replication services.
By having multiple systems in a common pool, IT departments can manage more data with fewer administrators, reduce training costs and in some cases extend the capabilities of their existing assets. A virtualized pool of multiple storage systems of various classes creates a tiered storage infrastructure to more closely align the cost of storing data to its value to the organization.
Data can be promoted or demoted across tiers automatically, according to a pre-defined policy. Sun offers disk storage system virtualization in both its midrange and enterprise class disk systems. Both provide a low-risk, "built-in" way to evaluate storage system virtualization.
As a market leader in data center virtualization, Sun can help organizations simplify data management, protect data, accelerate recovery, drive down the true cost of storage, and improve the day-to-day performance of data users across the network.
This article was the third and final in a series on virtualization technology. Sun also offers solutions for virtualization on X64 servers and at the operating system level with Solaris Containers.
Questions or comments? Please email education_news@sun.com
This article has been synthesized from the Sun BluePrints article, Slicing and Dicing Servers: A Guide to Virtualization and Containment Technologies, Harry J. Foxwell and Isaac Rozenfeld, October 2005.
| 
