The evolution of hierarchical storage management.

The process of automatically storing data on the lowest-cost devices
that can support the performance required by the applications. To users,
data storage never fills and file access, regardless of location in the
storage hierarchy, is completely transparent. The software automatically
manages multiple levels of storage hierarchy.
Excerpted with permission from Storage Manifesto
A paper by Fred Moore, president
Horison Information Strategies [c] 2002
www.horison.com

2004 marked the 30th anniversary of hierarchical storage management (HSM). IBM's invention of HSM is considered by many as the precursor to what is known today as Information Lifecycle Management (ILM). This fundamental technology helps address the need to save critical time and storage media costs by moving data from one medium to another. Originally called the virtual storage concept capable of managing one half a terabyte of data, this concept of helping mainframe customers move data from tape to a then-new disk-based storage medium remains relevant even in today's virtualized storage architectures.

As it turns 30 years old, HSM continues to give customers the ability to automate critical processes relating to the media on which data is stored, reducing storage media and administrative costs associated with managing data. With the hierarchical storage management and archive software market growing at a rate of 17% per year, according to Gartner, this approach continues to be one of the first steps organizations take in managing the value of their data.

HSM in Today's Storage Environment

The reason an IT manager might choose HSM as the "entry point" or "next step" toward evolving to an On Demand storage environment is because the manager is challenged with an environment that is growing rapidly and has identified classes of data that can be moved to lower-cost storage.

Many organizations struggle to understand how to determine the best data management method for managing inactive data and optimizing storage management systems. Because of the amount of data that can pile up--IDC claims the total number of e-mails sent daily worldwide is growing from 9.7 billion in 2000 to 35 billion in 2005--an HSM strategy employing both storage and content management is a necessary provision for customers.

HSM automatically moves infrequently-used data to less expensive and less accessible media. This is ideal for managing large files that need to be kept online for specific applications like imaging, digitized information, database logs and video streaming. When automated, HSM can also greatly reduce the time spent on data management.

IT administrators need this sort of approach. The ability to associate and move compliance data through a hierarchy of storage that considers cost, longevity and access speed is important for future-proofing data management systems and decreasing the cost of ownership associated with it. In addition, a hierarchical approach to storage can help provide disaster recovery options by saving copies of the data offsite and allowing customers to create a step-by-step disaster recovery plan.

All of this is transparent to users with the exception, perhaps, of some latency in retrieving files that might be stored on removable media. The theory is this: since high-performance storage space is expensive, why clutter it up with files that you are not actively using? Similarly, why overwhelm your backup system making it back up files over and over again despite the fact that they have not been touched in years?

HSM's Role in ILM

Today, customers are faced with increasingly complex decisions about the value and use of their data. The recent interest in ILM is being driven by new requirements for reporting and privacy. In these situations, the enterprise has to adapt its information management practices by deciding how long the information will be kept and how quickly the enterprise will need to access it. Both of these requirements are tricky for storage managers, because information loses value at various rates.

Implementing an ILM solution requires more than simply running e-mail management software or archive capabilities. Customers need to answer key business questions, such as the following: How valuable is this data? Can I ever delete it? How do I balance needs for the availability of this data and my storage budget?

ILM uses HSM architecture, but its scope is much larger: it is focused on managing data throughout the entire enterprise, not just on organizing storage schemes. ILM starts by looking at the enterprise's information and how it needs to be managed rather than with the technical roadmap that characterizes HSM. That broader view means that unlike HSM, which was almost entirely an IT initiative, ILM starts with the entire enterprise before it moves to the technology. Storage managers are certain to be involved in ILM projects, but they are not likely to be the leaders or the instigators.

Kami Snyder is marketing manager, ILM, at IBM Tivoli (Houston, TX)

www.ibm.com