Storage Resource Management

Today's unprecedented growth in data forces systems administrators to find new ways to manage storage capacity and use. Storage Area Networks (SANs) have provided some relief to the data explosion by enabling more servers to access larger storage arrays. SANs, however, only consolidate storage resources. Without storage-management applications, a SAN infrastructure can't determine what kinds of data are stored or identify where data should be placed.

Storage Resource Management (SRM) operates on a client/server model. The client is a small software utility installed on each file or application server. The SRM client software monitors the types of files and applications installed on the host system. The server is an SRM workstation that gathers information from each client and compares the results, making it possible to identify which clients have duplication of files or applications. The SRM workstation also makes it possible to monitor over- or underutilization of storage space.

Duplication is a major contributor to data growth. For example, a business might spread multiple copies of applications, databases, and files throughout its network. To remedy such inefficient use of storage capacity, storage administrators can use SRM applications to help them determine where resource duplication exists. (It's important to make a distinction between SRM and volume management—volume management only defines storage capacity; it doesn't identify duplication of files or applications.)

SRM applications are a natural complement to shared storage networks. Whereas SANs provide an efficient means to access storage, SRM tools ensure that redundant files or applications don't fill shared disk space. Minimizing data duplication also streamlines tape backups. Because administrators must often calculate the ongoing cost of administering storage on a per-gigabyte basis, any reduction in the volume of data to manage contributes to a lower total cost of ownership (TCO). Combining SAN technology with SRM helps ensure that IT departments can administer useful data more economically.

SRM also complements storage virtualization. The value of hiding the complexity of physical storage through virtualization is compromised if redundant applications and files glut the virtualized storage. Theoretically, it's possible to tightly couple SRM with storage virtualization so that an intelligent virtualization engine automatically allocates storage capacity as needed and monitors the types of data stored. (This capability remains theoretical because automated virtualization and SRM have not yet been combined on a single platform.) By automatically eliminating redundancy, future versions of virtualization can contribute to lower administrative overhead and hardware costs.

HighGround Systems, which Sun Microsystems acquired in 2001, pioneered SRM software, basing its innovative approach to storage management on intelligence gathering by software agents installed on each server. Each SRM software agent constantly monitors storage use on disk arrays under a server's control. Each server reports information on the types of applications, databases, and files to a central-management platform. By processing the information gathered from servers, the SRM platform can identify duplication, and storage administrators can determine the best way to eliminate redundant applications and data.

One of SRM's initial drawbacks was the requirement that software agents run on each server in the network. IT departments don't like to load third-party software onto their servers, even if the software serves a useful purpose. If a server fails, for example, someone must remember to reload the proper version of SRM software. A new release of SRM agent software also requires a lengthy installation process on multiple servers. As with volume management, the resolution to this problem is to integrate SRM functionality into the OS. You can then automate updates more easily because installation occurs as part of a typical service pack upgrade.

Over time, storage administrators will benefit from the convergence of SAN management, volume management, storage virtualization, and SRM applications. As Microsoft's announcements at last month's Windows Hardware Engineering Conference (WinHEC) show, OS vendors are recognizing the key role that storage continues to play in enterprise networks. Integrating intelligent SRM agents into the OS simplifies the storage process and helps contain the unrelenting growth of data.