partition customization ....how do I ???

[birger]

On Wed, 2010-03-03 at 22:47 -0500, Gene Heskett wrote:
> >
> In this case, same motherboard, same sata0 connector.  This board has 6 or 7 
> sata ports. 4 in use ATM.

But not the same drive, right?

So I wouldn't exclude the rather obvious explanations that the drive
could be slower, failing or that the drive could be set to some
'compatibility mode' geometry through jumpers that yielded a non-optimal
file system. Another possible culprit would be the cables.

I think that blaming diskdruid for this kind of speed difference without
actually considering the more obvious possibilities is a bit weird. Did
you repartition your slow disk manually and rsync back to see if you got
it faster?

Errors in file system layout on old (slow) disks *can* make a big
difference. One problem is that some disks have been set up to lie about
their real geometry in order to work with an old BIOS. Optimizing a file
system layout for such a disk would be impossible without knowing the
details of how the disk maps the advertised geometry to the real one.
Check your disk documentation and use the optimal jumper settings if
your BIOS can handle it.

When you really know what is going on right down to the platter you can
optimize a lot. I wrote my own program to low-level format floppies on
my BBC B back in the mists of time. 30% speed increase for sequential
IO. :-)

For the case you refer to I would still first check and recheck the
configuration of that disk, and then try a fresh F12 install. And I
would just use the default DD partitioning. If the disk really is weird
enough that DD can't optimize for it I would just buy a new disk. They
are so cheap these days I wouldn't bother spending much time on it.


birger