Problem:
The Mac WD Drive Manager crashes when trying to rebuild the RAID array on the My Book Premium II external hard drive.

Cause:
Appears to be an issue with Mac 10.5 and 1394 Firewire. There are no known issues with Mac 10.4.x or USB.

Solution:
Connect the drive to the USB port, and re-run the WD Drive Manager to reconfigure the RAID to the desired array.

If you install and use a desktop edition hard drive connected to a RAID controller, the drive may not work correctly unless jointly qualified by an enterprise OEM. This is caused by the normal error recovery procedure that a desktop edition hard drive uses.

When an error is found on a desktop edition hard drive, the drive will enter into a deep recovery cycle to attempt to repair the error, recover the data from the problematic area, and then reallocate a dedicated area to replace the problematic area. This process can take up to 2 minutes depending on the severity of the issue. Most RAID controllers allow a very short amount of time for a hard drive to recover from an error. If a hard drive takes too long to complete this process, the drive will be dropped from the RAID array. Most RAID controllers allow from 7 to 15 seconds for error recovery before dropping a hard drive from an array. Western Digital does not recommend installing desktop edition hard drives in an enterprise environment (on a RAID controller).

Western Digital RAID edition hard drives have a feature called TLER (Time Limited Error Recovery) which stops the hard drive from entering into a deep recovery cycle. The hard drive will only spend 7 seconds to attempt to recover. This means that the hard drive will not be dropped from a RAID array. Though TLER is designed for RAID environments, it is fully compatible and will not be detrimental when used in non-RAID environments.

Please Note:   Depending on how the WD ShareSpace RAID is setup, that RAID array may not be recoverable from a drive failure.

Qty of 2 – 1TB internal hard drives:

• RAID-0 – 2TB – (Not recoverable)
• RAID-1 – 1TB – (Recoverable)
• RAID-5 – (Not Supported)

Qty of 3 – 1TB internal hard drives:

• Spanning – 3TB – (Non recoverable)
• RAID-0 – 3TB – (Non recoverable)
• RAID-1 – (Not Supported)
• RAID-5 – 2TB – (Recoverable)

Qty of 4 – 1TB internal hard drives:

• Spanning – 4TB – (Non recoverable)
• RAID-0 – 4TB – (Non recoverable)
• RAID-1 (Double Mirror) – (Recoverable)
• RAID-5 – 3TB – (Recoverable)

For a recoverable RAID mode:
To recover the ShareSpace from Drive failure, or from a degraded RAID array, you must replace the failed drive with a Western Digital unformatted drive of the same model and size. Once the drive is replaced, the ShareSpace will re-sync the drive back into the RAID array and automatically start the RAID re-build. No further user intervention is needed, other than replacing the failed drive in the unit.

Standard RAID levels – Wikipedia, the free encyclopedia
A RAID 0 can be created with disks of differing sizes, but the storage space added to … RAID 0 implementations with more than two disks are also possible, …
en.wikipedia.org/wiki/Standard_RAID_levels
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RAID Level 0
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Beginners Guides: Installing RAID on a Desktop PC – PCSTATS.com
Abstract: With the right number of identical hard drives, motherboards that support RAID can choose from RAID 0, RAID 1, and sometimes even RAID 0+1 for …
www.pcstats.com/articleview.cfm?articleID=830

AC&NC | RAID.edu – RAID Levels – RAID Level 0 – RAID 0
Complete description and an easy-to-understand diagram of RAID level 0. Advantages and disadvantages of RAID 0 are also discussed.
www.acnc.com/04_01_00.html

OCZ Vertex SSD RAID-0 Performance | OCZ Vertex RAID-0,OCZ Vertex …
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The PhotoFast CR-7200 MicroSDHC RAID-0 CF adapter
Now this is a good idea: RAID together four 16GB MicroSDHC cards for a fast, 64GB Compact Flash card. I guess in theory …
www.crunchgear.com/…/the-photofast-cr-7200-microsdhc-raid-0-cf-adapter/

The Software-RAID HOWTO: RAID setup
The chunk-size affects read performance in the same way as in RAID-0, … On RAID-5, the chunk size has the same meaning for reads as for RAID-0. …
tldp.org/HOWTO/Software-RAID-HOWTO-5.html