ILM And Its Relationship To Tiered Storage

Regulations such as the Sarbanes-Oxley Act and the Health Insurance Portability and Accountability Act (HIPAA) are forcing many organizations, large and small, to retain information at a much faster rate and in vastly greater amounts for much longer than ever before. In addition, that information must be more readily accessible, making tape less practical. These requirements are forcing IT organizations to rethink their storage strategies. No longer can companies think of meeting their escalating storage needs only in terms of off-line tape or undifferentiated disk. For most organizations today, off-line tape may not meet restore-side performance or reliability requirements, and brings with it onerous management and IT staffing issues. Fast, reliable disk, on the other hand, may be too expensive to meet all compliance requirements.

One disk technology that shows promise for satisfying these new requirements is Serial Advanced Technology Attachment (SATA). SATA is a serial interface to the ATA disk drive that builds on the success of Parallel ATA but offers improved performance and reliability, as well as reduced interface complexity. Equally important, SATA continues the considerable cost advantage and raw capacity of Parallel ATA over Fibre Channel (FC) and SCSI drives. Organizations cannot simply start using SATA instead of tape, however. Now, more than ever, it is vital to carefully plan what kinds of information should be stored on which types of storage media and when, if ever, that information should be moved from one type of storage media to another.

In addition, undifferentiated SATA disk may be just additive to the overall management problems of undifferentiated FC or SCSI disk. In response to this, another technology was developed and is now available that is used in conjunction with SATA. This technology is called Massive Array of Idle Disks, or MAID. MAID is the key technology that allows SATA to reach its promise in regards to a costefficient as well as operationally efficient tiered storage strategy. To address the management issues of implementing such a strategy, a systematic methodology called information lifecycle management (ILM) has been developed out of several commonly accepted practices.