For years companies have been deploying Massive Arrays of Idle Disks technologies to reduce data-storage energy costs.
For years companies have been deploying Massive Arrays of Idle Disks to reduce data-storage energy costs. The on/off or spin/no spin approach reduces 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%.
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% of the power used in data storage and, while both MAID 1.0 and MAID 2.0 help conserve power, MAID 1.0 has such a negative effect on application performance it is not practical in most circumstances. The goal of MAID 2.0 is to deliver energy savings to the broadest set of applications without impacting application 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% 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%. 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.
Level 2 MAID 2.0, often implemented after 30 minutes of disk-drive inactivity, reduces the speed of the drive platters by 50%. The first I/O request will be handled within 15 seconds, and subsequent requests will be handled instantaneously. This level achieves an energy savings of at least 40%, and generally is used for data that is occasionally — but not frequently — accessed, such as archived word-processor files, spreadsheets and presentations.
Level 3 MAID 2.0 places a drive into a light sleep, yet able to respond to an initial I/O request within 30 seconds. As with the other MAID 2.0 levels, subsequent I/O requests are handled instantaneously. Many users deploy Level 3 MAID 2.0 after 60 minutes of inactivity. This enables energy savings of 60% or more, and is ideal for long-term archiving of such fixed-content data as e-mails, financial records and medical tests.
Obviously the MAID 2.0 approach is more flexible and efficient than the MAID 1.0 approach, which spins a drive at 100% or 0%, offers no flexibility in energy savings and reduces application performance. The energy savings enabled by MAID 2.0 solutions are impressive and substantial in any light, but what is even more remarkable is that many non-MAID 2.0 storage systems take 60 to 120 seconds to respond to an I/O request without achieving any energy savings at all.
MAID 2.0 products reduce this response time by as much as 75% and enable substantial energy and cost savings. MAID 2.0 is the energy-efficient data-storage technology with the widest utility. It does not compromise performance, it is easy to implement and it addresses the core cost issue — disk-drive energy use. MAID 2.0 users receive energy savings of 20% to 60% or more and, in many cases, enjoy even better performance than alternatives that are not energy-efficient.
Woolery is the Senior Vice President of Marketing at Nexsan.
