For years companies have been deploying Massive Arrays of Idle Disks technologies to reduce data-storage energy costs. The on/off or spin/no spin approaches reduce energy consumption by putting power-hungry disk drives to sleep when they are not being used.
Early versions of MAID products -- whether you think of them as first-generation MAID, MAID 1.0 or "old MAID" -- have two shortcomings, however. First, spun-down drives typically take several minutes to spin back up: That's an unacceptable length of time and results in an unacceptable loss of performance for most applications. Second, most MAID 1.0 providers support only a limited percentage of active disks at any given time, frequently as few as 25 percent.
MAID 2.0 broadens energy-saving options by adding multiple modes -- instead of the binary on/off approach of MAID 1.0 -- that are designed to accommodate different types of data. For instance, such files as financial records and medical test results need to be stored for several years or even much longer, but their data doesn't change. An X-ray, for example, needs to be stored, but it typically is not accessed frequently if at all; and it is never altered. Such fixed-content data is ideally suited for MAID 2.0 applications.
Disk drives consume 80 percent of the power used in data storage, and unless technologies focus on solving this specific issue, they missing the point. Both MAID 1.0 and MAID 2.0 meet this critical criterion, but MAID 2.0 delivers the additional benefit of performance assurance. The MAID 1.0 approach of turning off spinning disk drives can achieve significant power savings; but because this practice has such a dramatic and negative effect on application performance, it is not practical in most circumstances. The unwavering goal of MAID 2.0 technologies is to deliver energy savings to the broadest set of applications without affecting their performance.
MAID 2.0 products achieve this goal by operating at user-defined and application-dependent energy-saving levels. A Level 1 setting signifies the fastest response time that still makes energy savings possible. A Level 1 setting would be ideal for such busy organizations as hospitals, which need fast access to patient X-rays or records, but can save energy when there are idle periods.
Many people incorrectly believe that 24/7 operations' data centers never experience idle time. However, according to a recent information-access study by researchers at the University of California, Santa Cruz, 90 percent of all stored data was not touched during a three-month time frame. Being open for business doesn't mean that all of an organization's storage disks need to be spinning at full speed.
A typical user might elect to put his storage devices into Level 1 MAID 2.0 after 15 minutes of inactivity. At that point, the read/write heads will be unloaded automatically. This simple step, transparent to the user, reduces air resistance and makes for an energy savings of approximately 20 percent. It maintains a sub-second response time without a power spike for the first I/O request. All subsequent I/O requests are handled instantaneously.