On 2011/07/26 21:30, Yasha Karant wrote:
> For reasons that are irrelevant to this discussion, we have ended up with a
> number of new workstations with WD Advanced Format "green" 1.5 TByte drives.
> We have been experiencing a number of difficulties that had to do with
> partition boundaries, etc. After a bit of digging, I found:
>
> http://community.wdc.com/t5/Desktop/Problem-with-WD-Advanced-Format-drive-in-LINUX-WD15EARS/td-p/6395
>
>
> Is anyone using a WD Advanced Format drive with SL 6? We are not and
> probably will/can not use LVM, but rather standard ext 2, 3, or 4
> partitions, included the extended partition model.
>
> If you are using this type of drive, information on the specifics of the
> formatting command(s) and syntax to use these WD drives would be
> appreciated. Any link to a detailed document or URL would be appreciated.
>
> Yasha Karant

I know what I would attempt in a pinch. I sort of "dig" partition formats
having been one of the guilty parties for the Amiga partitioning scheme.
It led me to doing obscene things and realize they often work.

I notice that fdisk has a mode for creating partitions based on block
number rather than artificial cylinders.

With that as a base tease out of what data you can find the actual
physical block size on the WD drives. Set up a small dummy partition
that ends on a 512 BYTE "cylinder" boundary that is also the end of
a physical block. Then carefully size all the partitions so that they,
too, have an end block that matches the end of a physical block. I've
heard of physical block sizes from 2048 BYTES to 16384 BYTES. I've not
yet heard of disks that use full physical cylinders as a block size,
which is good because disks are "notched" as a general rule. The number
of BYTES per track varies to keep bit density high. (I gather the old
Commododo floppy disks did this, too. CDROMs automatically do it with
their spiral layout.)

So you might check to see if the low level format of the WD drive is
documented, whether its blocks are always the same size, and what that
size might be. Then make your disk layout to very carefully optimize
this. Accidents of original design made this a non-issue on the Amiga.
But it's certainly an issue on most any other OS when working with
artificial cylinders that are 255*63*512 BYTES in size - no nice even
divisors in sight.

If this sort of trick does not work I'd get in touch with any of their
actual firmware designers you can discover and learn what they recommend.
(I fondly remember my taps into Micropolis and Maxtor, may those companies
rest in peace.)

{^_^}   Joanne