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5.5.2 HDD Power Management
MAID (Massive Array of Idle Disks) is a storage technology that employs a large group
of disk drives in which only those drives in active use are spinning at any given time.
This reduces power consumption and prolongs the lives of the drives.
MAID is designed for Write Once, Read Occasionally (WORO) applications such as Data
Backup, Document, Mail server, and so on.
MAID technology focuses on "Green Storage Concept" to save power consumption and
enhance disk drives effective usage, i.e., "disk drives are spun down when there is no
activity or I/O on the drives".
In the RAID subsystem, MAID is implemented in the HDD Power Management menu.
Using the Advanced Power Management (APM) function of disk drives, HDD Power
Management has three options (MAID Levels): (Level 1) Place idle drives in Lower Power
Mode, where the drives' heads are unloaded; (Level 2) Place idle drives in Low RPM
Mode, where drives' heads are unloaded and slows down to around 4000 RPM; and
(Level 3) Spin down idle drives, where drives stops spinning and goes into sleep mode.
Stagger Power On Control:
This option allows the RAID subsystem's power supply to power up in succession
each HDD in the RAID subsystem. In the past, all the HDDs on the RAID subsystem
are powered up altogether at the same time. This function allows the power
transfer time (lag time) from the last HDD to the next one be set within the range of
0.4 to 6.0 seconds. Default is 0.7 seconds.
Time to HDD Low Power Idle: (MAID Level 1)
This option enables the RAID subsystem to place idle HDDs of a Raid Set in Low
Power Mode, where drives' heads are unloaded. The power consumption of the Idle
HDD saving is around 15% to 20%. Recovery time is under a second.
Options are: Disabled, 2, 3, 4, 5, 6, and 7 (Minutes).
SAS to SAS/SATA RAID Subsystem
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