Nexsan Energy Efficient AutoMAID Technology

Wikibon has published a Green Validation Report entitled Nexsan Energy Efficient AutoMAID Technology.

A storage array consists of a large number of disk drives together with a storage controller. Many servers can be connected to a storage array, which allows any of the disk drives to be used by any server. Data is read from the disk and written to the disk with a read/write heads. The disk spins at between 7,200rpm and 15,000rpm. The heads are moved across the recording surface of the disk to different tracks where the data is stored.

In traditional storage arrays all the disks are spinning all the time, even when they were not reading or writing data. About 80% of the energy consumed by a storage array goes to spinning the disks and moving the read/write heads.

Nexsan has developed software and hardware features called AutoMAID, a sophisticated technology to turn off individual drives in an array when they are not being used. AutoMAID has 3 levels, saving progressively more power. When a disk drive goes into idle state for 10 minutes, the drive goes into AutoMAID level 1. After 10 more minutes with no I/O activity, it goes into AutoMAID level 2, and after 10 more minutes into level 3. The delay is added to avoid ‘hunting’ between AutoMAID levels, which would increase power momentarily when the disk became active.

Figure below shows power required for idle disks and for each level of AutoMAID. These figures were determined at Nexsan’s laboratory on Nexsan equipment under the guidance and supervision of Wikibon Energy Labs. Wikibon certifies the accuracy of the data.

The time that AutoMAID is invoked can be determined by running a standard report from each Nexsan array that itemizes the percentage of time each level of AutoMAID is used.

Wikibon has developed a Wikibon Energy Lab Power Calculator for AutoMAID to determine the power savings and the rebates.