HP 128MB SA641/642/E200 Battery Backed Write Cache 351580-B21 Fascicule

The following features offer detection of possible failures before they occur, allowing preventive
action to be taken:

S.M.A.R.T.: Self Monitoring Analysis and Reporting Technology first developed at Compaq
detects possible hard disk failure before it occurs, allowing replacement of the component
before failure occurs.
Drive Parameter Tracking monitors drive operational parameters, predicting failure and
notifying the administrator.
Dynamic Sector Repairing continually performs background surface scans on the hard disk
drives during inactive periods and automatically remaps bad sectors, ensuring data integrity.
Smart Array Cache Tracking monitors integrity of controller cache, allowing pre-failure
preventative maintenance.
Environment Tracking for External Storage System: Monitors fan speed and cabinet
temperature of ProLiant Storage System and newer HP storage enclosures.

Keeps data available and server running while a failed drive is being replaced; several fault
tolerance configurations are supported including:

Distributed Data Guarding (RAID 5): This allocates parity data across multiple drives and
allows simultaneous write operations. It is recommended for up to 14 hard drives.
Drive Mirroring (RAID 1, 1+0): This allocates half of the drive array to data and the other half
to mirrored data, providing two copies of every file. It is a high-performance RAID.

Minimizes downtime, reconstructs data, and facilitates a quick recovery from drive failure

Recovery ROM: This new feature provides a unique redundancy feature that protects from a
ROM image corruption. A new version of firmware can be flashed to the ROM while the
controller maintains the last known working version of firmware. If the firmware becomes
corrupt, the controller will revert back to the previous version of firmware and continue
operating. This reduces the risk of flashing firmware to the controller.
On-Line Spares: Up to two spare drives can be installed prior to drive failure. If a failure
occurs, recovery begins with an On-Line Spare and data is reconstructed automatically.

NOTE: On-Line Spares can only be used with RAID level 1, 1+0, and 5.

Consistency and Upgradeability make the Smart Array family unique in the industry:

GUI based configuration, management and diagnostic software tools
Common data format between generations of products
Data migration between servers and external storage enclosures

DA - 12067   Worldwide — Version 12 — September 5, 2007

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