Legal Commentary

Don't RAID Western Digital Drives

By Professor University of Miami School of Law

It seems that ordinary Western Digital (WD) hard drives have an “advanced” feature that makes them unsuitable for either hardware or software RAID. Since I like to mirror the family’s hard drives for security in the event of hard drive failure — we had one fail on my wife’s machine last week so this is hardly paranoia — this is something I am glad I found before placing an order.

Answer

Western Digital manufactures desktop edition hard drives and RAID Edition hard drives. Each type of hard drive is designed to work specifically in either a desktop computer environment or on RAID controller.

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).

I think the box should have a warning sticker about this…

Meanwhile, back to the hunt for reliable, very quiet, low-heat-producing, mass storage.

Full post as published by Discourse.net on February 07, 2008 (boomark / email).