Dell PowerEdge RAID Controller 5i - Manual (Page 19)

PERC 5 Features
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SMART Technology
The Self-Monitoring Analysis and Reporting Technology (SMART) feature monitors the internal
performance of all motors, heads, and physical disk electronics to detect predictable physical disk
failures. This feature helps monitor physical disk performance and reliability, and protects the data on
the physical disk. When problems are detected on a physical disk, you can replace or repair the physical
disk without losing any data.
SMART-compliant physical disks have attributes for which data (values) can be monitored to identify
changes in values and determine whether the values are within threshold limits. Many mechanical and
electrical failures display some degradation in performance before failure.
There are numerous factors that relate to predictable physical disk failures, such as a bearing failure, a
broken read/write head, and changes in spin-up rate. In addition, there are factors related to read/write
surface failure, such as seek error rate and excessive bad sectors.
NOTE:
See www.t10.org for detailed information about Small Computer System Interface (SCSI) interface
specifications and www.t13.org for Serial Attached ATA (SATA) interface specifications.
Background Initialization
Background Initialization (BGI) is a process to correct parity on the virtual disks. BGI is an automated
check for media errors in which parity is created and written in the process. BGI does not run on RAID 0
virtual disks.
NOTE:
You cannot permanently disable BGI. If you cancel BGI, it automatically restarts within five minutes.
See "Stopping Background Initialization" on page 67 for information on stopping BGI.
The background initialization rate is controlled by the storage management software. You must stop an
ongoing background initialization before you change the rate, or the rate change will not take effect.
After you stop background initialization and change the rate, the rate change will take effect when the
background initialization restarts automatically.
NOTE:
Unlike initialization of virtual disks, background initialization does not clear data from the physical disks.
NOTE:
Consistency Check and Background Initialization perform the same function. The difference between them
is that Background Initialization cannot be started manually, while Consistency Check can.
LED Operation
The LED on the physical disk carrier indicates the state of each physical disk. For internal storage,
see your system documentation for more information about the blink patterns.
For blink patterns on the Dell PowerVault™ MD1000, see the Dell PowerVault MD1000 Hardware
Owner’s Manual. For blink patterns on the Dell PowerVault MD3000, see the Dell PowerVault MD3000
Hardware Owner’s Manual.
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