Promise Technology Version 4.4 user manual Controller Cache, Disk Parameters, Rebuild Setting

Chapter 5: RAID Monitoring and Maintenance

Controller Cache

Allows you to toggle between two write modes for the FastTrak's cache:

Write Through – Data is written to the cache and hard drive at the same time. This arrangement is safer. Check the box to select it

Write Back – Data is written to the cache first and to the hard drive later. This arrangement increases performance at the risk of data loss if the power fails. Uncheck the box to select it.

Disk Parameters

Check the respective boxes to enable these features:

Enable Write Cache – Speeds hard disk performance by writing data to the cache to increase performance. Note that you can lose data if a power failure occurs.

SMART Check – SMART, an acronym for Self-Monitoring Analysis and Reporting Technology, is a feature of the disk drive software. It monitors the internal performance of the drive and reports to the PC when it finds a potential failure. SMART warns you of a developing drive failure so you can replace the drive before it actually fails.

Rebuild Setting

Check the respective boxes to enable these features:

Enable Hot Spare Disk – Enables a spare drive not assigned to the array to automatically replace a failed drive in the array. You must also enable Auto Rebuild for this feature to be effective.

Enable Auto Rebuild – Enables automatic rebuilding of a fault-tolerant (RAID 1, 0+1 and 5) array when it goes Critical.

Enable Hot Swap Disk – Allows you to replace a faulty disk drive without shutting down the system. This feature works with an externally replaceable disk drive enclosure such as the Promise SuperSwap.

Rebuild Setting – Allocates system resources between rebuilding the array and responding to read/write commands from the computer system.

A High setting assigns most of the system resources to rebuilding. Rebuilding goes faster, restoring redundancy sooner but read/write requests are handled slower.

A Low setting assigns most of the system resources to handling read/write requests. Read/write requests are handled at nearly normal speed while the rebuild takes longer.

See Rebuild an Array later in this chapter for more information on the rebuilding process.

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