24 Storage Controller FeaturesPhysical Disk Power ManagementThe PERC H700 and H800 cards can be configured to spin down certain harddrives after a set amount of time of inactivity to conserve power. Thispower-savings feature is disabled by default and can be enabled in the DellOpenManage storage management application.The power-savings feature can be enabled so that unconfigured disks, hotspares, or both are spun down. The amount of time to wait to spin down thesedisks can also be set. The minimum amount of time to wait that can be set is30 minutes and the maximum is 1 day. The default is 30 minutes.Disks that are spun down automatically, spin up when they are needed foruse. When a system is rebooted, all disks spin up.Using the SMART FeatureThe Self-Monitoring Analysis and Reporting Technology (SMART) featuremonitors the internal performance of all motors, heads, and physical diskelectronics to detect predictable physical disk failures. The SMART featurehelps monitor physical disk performance and reliability. SMART-compliantphysical disks have attributes for which data can be monitored to identifychanges in values and determine whether the values are within thresholdlimits. Many mechanical and electrical failures display some degradation inperformance before failure.A SMART failure is also referred to as a predicted failure. There are numerousfactors that relate to predicted physical disk failures, such as a bearing failure,a broken read/write head, and changes in spin-up rate. In addition, there arefactors related to read/write surface failure, such as seek error rate andexcessive bad sectors. For information on physical disk status, see "DiskRoaming" on page 26.NOTE: For detailed information on SCSI interface specifications, see t10.organd for detailed information on SATA interface specifications, see t13.org.
