disk utility benchmarking problems

[Alan McKay]

Hey folks,

I am running 11.04 and go into the disk utility and select my USB
drive because I want to run a benchmark on it with the benchmarking
feature of the disk util.

At first it told me the disk had to have no partitions so I wiped them
and tried again.

Now it says it fails because "the disk seems to have usage raid -
write benchmarking requires the disk to be completely empty"

So I google that and check this list.  In google I found the same
problem and they fixed it by using dd to wipe the MBR

dd if=/dev/zero of=/dev/sdb bs=512 count=1

So I tried that and still get the same error.  Even if I write zeros
for a much longer time than just count=1

Any ideas?

thanks,
-Alan

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