David G. Lawrence dg at
Fri Feb 25 20:18:52 GMT 2005

> > > Under heavy load (I/O load on the disks constantly over 200 tps, average
> > > at about 250 tps, peaks over 600 tps) a random drive disconnects from
> > > the RAID 10. After removing the drive from the config and rescanning the
> > > bus, the drive does not show up anymore. The only way to get the drive
> > > back is to unplug the drive (or switch the computer off, so that power
> > > is removed).  After that there is no problem to rebuild the RAID with
> > > the drive.
> > 
> > Interesting. AFAIR the same sort of errors occured with some older WD
> > drives and 3Ware 750x controllers.
> > The solution was to flash the drives firmware.
> > 
> > A quick googling found some reference to the problem on this document:
> >

   ...and here is even more information about the problem:

 	Why do EIDE drives disappear from the IDE RAID array or system after
a short period of error-free operation?

Affected drives:

WD EIDE drives with capacities between 40GB & 120GB
WD EIDE drives with greater than 120GB capacity with a date earlier than

WD EIDE drives are dropped from an IDE RAID array or system after several
days or weeks of error-free operation.

The problem is a result of a feature that reduces idle acoustic noise in
desktop drives. This feature may cause a timeout likely (though not
exclusively) in an IDE RAID environment. To disable the feature, you can run
a simple Western Digital utility to turn off a single bit in the drives
run-time configuration. Disabling of this feature will NOT impact normal
system operations. No firmware or hardware changes are required.

IDE Upgrade Utility (Non-3Ware controller cards)
For all configurations other than 3Ware controller cards, download the IDE
Upgrade Utility for the Desktop PC.

3Ware controller cards
If you are using one or more 3Ware controller cards in an IDE RAID
configuration, download the IDE RAID Compatibility Upgrade Utility for 3Ware
7500-X controllers cards.


David G. Lawrence
Download Technologies, Inc. - - (866) 399 8500
TeraSolutions, Inc. - - (888) 346 7175
The FreeBSD Project -
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