With all the press coverage about the growth of open systems, IT management may forget that mainframe-based DASD remains the backbone of most large enterprises because the majority of mission-critical data and applications still depend on the mainframe. Mainframe systems are an attractive, valuable resource because they’re:
- Relatively inexpensive in terms of storage costs
- Architecturally streamlined
- Effective in running proven software
- Stable and mature enough that best practices and policies are established
- Robust in processing strength
- Precise enough to control the rate of work from single host systems to huge parallel sysplex configurations.
Despite these factors, a crisis is brewing in the mainframe space. Growth slowed, but didn’t stop, during the recession. Head count was trimmed, but deadlines remained the same or were accelerated. Problems that hampered the open systems community happened on a smaller scale in the mainframe world.
Storage-related issues for mainframes are largely similar to open systems. Disk arrays are physically identical, with differences deeply buried in the microcode of the arrays. Storage Area Networks (SANs) are little more than the open systems version of the ESCON and FICON prevalent in mainframe systems for years. Also, application changes to support industry initiatives, such as compliance demands, are putting more pressure on mainframe storage. For example, companies are required to keep more data for longer periods—and still be able to recall that data on a moment’s notice. The mainframe is an appealing choice for this because data stored on the mainframe is less expensive and more secure than data stored on open systems platforms.
Mainframe storage administrators face several challenges: