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Mainframe versus Non-Mainframe Systems Efficiency - A Widening Gap
Average disk allocation levels for UNIX, Linux and Windows systems are low and average just 30 to 45 percent of total drive capacity while mainframe disk storage averages 80 percent allocation or better significantly improving the cost-effectiveness of disk storage. Many non-mainframe disk suppliers are just now touting the concept of "thin provisioning" as a new breakthrough for improved disk utilization and reducing over-allocation of disk space. However, this concept is not new and first appeared with the JCL SPACE parameter (as the Release sub-parameter (RLSE)) in 1965 on the OS/360 operating system. Thin provisioning will help improve the poor utilization levels that are the norm for non-mainframe systems.
Integrated VTL (Virtual Tape Libraries) offer improved utilization for tape storage and were pioneered on the mainframe in 1997 by IBM and StorageTek. Integrated VTLs reduce the number of physical tape cartridges by placing multiple virtual tape volumes on a single physical cartridge. Cartridge utilization commonly reaches 80 percent or more compared to much lower average tape utilization levels without Integrated VTLs. With fewer cartridges, the number of drives and the number of libraries can also be reduced providing significant Capex and Opex reductions. Ten years later, Integrated VTLs are just beginning to enter the non-mainframe storage market as tape usage for these systems is quickly advancing beyond just backup/recovery and into true tier 3 applications such as fixed content, compliance and archive. Optimizing all storage assets by improving storage utilization and getting the right data in the right place is a primary storage management goal with huge payback for storage administrators.
Server utilization levels for non-mainframe systems rarely range above 25%. Since many servers in non-mainframe systems are used for a single application compared to the high multi-processing levels of the mainframe, it is often difficult to drive up utilization from a single application. Without higher degrees of multi-tasking, utilization levels for non-mainframe servers will remain low and the number of servers will remain high. Virtual machine architectures are aiming to improve this directly by allowing several virtual machines to execute on a single physical machine.
Bottom line: A powerful suite of software offerings enable processor and storage utilization levels to be significantly higher on mainframes than on non-mainframe systems. The greater efficiencies usually translate into significant up-front capital expense and ongoing operating expense savings.
Source: Horison Information Strategies: Storage Spectrum
© 2008 Horison
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