The challenges of high-performance storage systems to help applications process tier 1 and tier 2 data still remain, and traditional MAID, where drives are powered off, is unlikely to help. However, the relative growth of tier 3 & 4 data is much higher. The lack of classification systems means that the data has to be kept even though a large percentage of it is rarely accessed or modified. This “Tier Omega” (Tier Ω) can benefit substantially from emerging MAID technologies.
Traditionally tape has been used for tier Ω. While tape has and will continue to have a significant role in mobility and recovery, it is ill suited to recovering random data elements. High-density disk storage systems from many vendors are becoming equivalent to automated tape systems in density of data stored (GB/sq. ft.) The advent of enterprise disk drives that will tolerate being turned off multiple times together with power management features such as parking heads, slowing disks down, and putting disks into sleep mode are making such disk based systems much more power efficient. This is illustrated in Figure 1. Other capabilities are turning MAID on and off to schedule, and it is likely that future enterprise disk drives will have increased granularity of power control and increased speed of time to be on line. Array vendors will focus on reducing the controller and array infrastructure overheads to reduce standby overheads to a minimum.
There are many application that can currently take advantage of MAID technologies, such as archive, sequential applications such as scientific, geophysical and entertainment,backup and VTL, and some NFS & CIFS based applications The main barrier to the expansion of adoption of these power-saving technologies lies with the server operating and file systems. Unless the application “knows” that the data is coming from a power-managed disk, the system (or user) is likely to time-out. From a systems point of view, applications should be able to "know" that MAID is being used, and (for example) "wake-up" drives if necessary.
Action Item: MAID-aware operating and file systems together with MAID-enhanced arrays can bring substantial energy savings. CTOs in organizations large and small should pressure developers in general and Microsoft in particular to implement MAID awareness for tier Ω, perhaps as part of a wider capability to interrogate where data is currently stored.
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