Re: Good news / bad news - The joys of RAID

[hpa@zytor.com (H. Peter Anvin)]

Followup to:  <200412021147.12410.systemloc@earthlink.net>
By author:    TJ <systemloc@earthlink.net>
In newsgroup: linux.dev.raid
> 
> I do not think the deathstar incident was due to a firmware problem as you 
> describe at all. I had a lot of these drives fail, and I read as much as I 
> could find on the subject. The problem was most likely caused by the fact 
> that these drives used IBM's new glass substrate technology. This substrate 
> had heat expansion issues which caused the heads to misalign on tracks and 
> eventually cross write over tracks, corrupting data. The classic "click of 
> death" was the sound of the drive searching for a track repetitively. In some 
> cases a format would allow the drive to be used again, in many cases it would 
> not. It is my belief that formatting was inneffective at fixing the drive 
> because the cross writing probably hit some of the low level data, which the 
> drive cannot repair on a format.
> 

It's also worth noting that there was extremely high correlation
between which factory built the drives and the failure rates.
Apparently some factories had virtually zero instances of this
problem.

	-hpa