Features, Smart technology, Patrol read – Dell PERC 4/SI User Manual
Page 23: Background initialization
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Features
Dell™ PowerEdge™ Expandable RAID Controller 4/Di/Si and 4e/Di/Si User's Guide
PassThru (Legacy) SCSI Channel
RAID Configuration Information
Supported Operating Systems and Drivers
RAID Controller Specifications
This section describes the features of the RAID controller, such as the configuration features, array performance features, hardware specifications, RAID
management utilities, and operating system software drivers.
Compatibility with Arrays Created on Existing RAID Controllers
The RAID controller recognizes and uses drive arrays created on existing RAID controllers without risking data loss, corruption, redundancy or configuration
loss. Similarly, the arrays created on the PERC 4/Di/Si and 4e/Di/Si controllers can be transferred to other PERC 4/Di/Si and 4e/Di/Si controllers.
SMART Technology
The self-monitoring analysis and reporting technology (SMART) detects predictable drive failures. SMART monitors the internal performance of all motors,
heads, and drive electronics.
Patrol Read
Patrol Read involves the review of your system for possible hard drive errors that could lead to drive failure, then action to correct the errors. The goal is to
protect data integrity by detecting physical drive failure before the failure can damage data. Patrol Read adjusts the amount of RAID controller resources
dedicated to Patrol Read operations based on outstanding disk I/O.
Patrol Read starts only when the controller is idle for a defined period of time and no other background tasks are active, though it can continue to run during
heavy I/O processes.
You can use the BIOS Configuration Utility to select the Patrol Read options, which you can use to set automatic or manual operation, or disable Patrol Read.
See
Patrol Read
in
RAID Configuration and Management
for detailed information about Patrol Read.
Background Initialization
Background initialization is the automatic check for media errors on physical drives It makes sure that striped data segments are the same on all physical
drives in an array.
The background initialization rate is controlled by the rebuild rate set using your array management software. The default and recommended rate is 30%. You
must stop the background initialization before you change the rebuild rate or the rate change will not affect the background initialization rate. After you stop
background initialization and change the rebuild rate, the rate change takes effect when you restart background initialization.
NOTE:
If you have questions about compatibility, contact your Dell Support Representative.
NOTE:
Pause/Resume is not a valid operation when Patrol Read is set to Manual mode.
NOTE:
If you cancel background initialization, it automatically re-starts within 5 minutes. You cannot permanently cancel the background initialization.