User guide

Hard Drive Arrays
The RA4000 Controller and the network operating system offer several other
fault management and data reliability features, including:
■ Auto reliability monitoring
■ Dynamic sector repairing
■ Drive parameter tracking
■ Drive failure alert features
■ Interim data recovery
■ Automatic data recovery
Auto reliability monitoring (ARM) is a background process that scans hard
drives for bad sectors in fault-tolerant logical drives. ARM also verifies the
consistency of parity data in drives with data guarding or distributed data
guarding. This process assures that you can recover all data successfully if a
drive failure occurs in the future. ARM operates only when you select
RAID 1, RAID 4, or RAID 5.
Using the dynamic sector repairing process, the controller automatically
remaps any sectors with media faults it detects either during normal operation
or during auto reliability monitoring.
Drive parameter tracking monitors more than 15 drive operational parameters
and functional tests. This includes parameters such as read, write, and seek
errors, spin-up time, cable problems, and functional tests such as track-to-track
seek time, one-third stroke, and full stroke seek time. Drive parameter tracking
allows the array controller to detect drive problems and predict drive failures
before they actually occur.
Drive failure features produce various drive alerts or error messages depending
on the Compaq server model. Refer to the documentation included with your