Media Management

As systems and storage administrators wrestle with ever-growing data volumes and varying requirements for retaining data, one solution that many are considering is information, or data, lifecycle management. Data lifecycle management assumes that all data either has a finite lifespan or should be archived indefinitely. An additional assumption is that the value of data changes over time.

As data ages and increases or decreases in value (according to the applications that depend on the information the data contains), migrating data to offline media such as optical media, DVD, or magnetic tape is frequently necessary. To ensure access to stored offline data and manage the data according to any applicable government and corporate regulations, systems and storage administrators need to deploy some form of media management.

Media management is an often-overlooked function of information management. Many backup, Hierarchical Storage Management (HSM), and archiving products provide some level of media management; however, few products provide the truly robust tools that sophisticated and complex information lifecycle management requires.

Sound media management practice includes both onsite and offsite capability. Managing onsite media encompasses ensuring that storage media are available for multiple uses, including initializing new media (e.g., writing to additional media), appending additional data to stored data, and retrieving or recovering stored data. Media management software should recognize which uses a specific media volume is designated to provide; typically the management application assigns attributes to the volume that designate which purposes the media will serve. Software that uses the media can then use the attributes to verify how the media volume is allocated before overwriting data. Effective media management applications display a media volume's attributes through use of a unique label—such as a six-character ANSI label that you can assign to an individual piece of media and can provide management functions. In addition, when the label is written directly to the media, you can use the lable to ensure that valid data is not overwritten when applications mount the media for write purposes.

Other important attributes that onsite media management requires include ownership information: For example, who owns the media? What programs use the media? Format is another important attribute. For example, does the media use ANSI, EBCDIC, or a proprietary format? Also important is information about multivolume sets (i.e., pointers to previous and subsequent volumes). Date information about each media volume should include information about when the media was initialized, when it was last written to, and when it was last mounted (for read or write).

Good media management software should let you remove media volumes that become undependable. You can measure media dependability by tracking factors such as mount count and I/O error count. For example, if a media volume's I/O error count is low and the mount count is high, or if the I/O error count is high and the mount count is low, you need to take the volume out of service. Verification is another important media management function. Periodically mount aging media volumes and run a verification pass against the data to ensure that the data is uncorrupted.

Offsite media management is equally as important as onsite media management. Media management software should let you move media volumes or multivolume sets from one location to another and should support as many locations as your information management policies require. The software should let you designate when specific media volumes are to be moved off site, moved from site to site, and moved back on site. Providing as much information as you can for offsite media is important. For example, if your company ships media off site in containers, each media volume should record its container name.

To effectively manage storage media, the best media management software tracks all the attributes associated with each media volume. Such software lets storage and systems administrators generate reports about various attributes and process these reports by location (i.e., onsite and offsite) and by the state of the media (i.e., allocated or available for use). Software media management tools have long been available for the mainframe and for OpenVMS. Many high-quality products on the market supply most or all of the same functionality for distributed systems environments. As data protection, compliance with regulatory requirements, and information lifecycle management grow in importance, IT departments should consider comprehensive media management an investment in solid information management practice.

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