IT managers interested in improving their bottom line will find a useful economy in the BigAdmin article on Managing the Power Used by Idle Disks in Servers Running the Solaris 8 OS or Above, which notes that idle spinning SAS disks can consume several watts and that managing multiple disks can result in substantial power cost reductions. Spinning down a SAS disk can save two to four watts, and spinning down older SCSI disks can save even more, the writer observes. While disk spin-up is an automated feature of the Solaris Operating System (Solaris OS), a disadvantage does exist in the amount of time that is required to spin up an idle disk, which can require as much as 10 seconds. Some considerations that govern the decision to spin-down or not are reviewed.

Guidelines for Disk Power Management

• Situations in which it is advisable to power-manage disk: The disk is not used. (The disk is neither mounted nor accessed as a raw device.) The disk is part of a group of disks reserved for performing scheduled backups. A specific disk is busy during a predictable period and idle during the rest of the time.

• Situations in which it is not advisable to power-manage a disk: The disk is a boot disk. The disk is accessed by mission-critical tasks where time-to-response is important. The disk is in service to global time-zone applications.

The paper then outlines the seven steps involved in enabling Solaris disk power management, providing code samples as necessary. [...read more...]

		fullsource
Print Email Current Profile Archive Blog Generate newsletter