Fixing Mis-replicated blocks

[John Meagher]

After a hardware move with an unfortunate mis-setup rack awareness
script our hadoop cluster has a large number of mis-replicated blocks.
 After about a week things haven't gotten better on their own.

Is there a good way to trigger the name node to fix the mis-replicated blocks?

Here's what I'm using for now, but it is very slow:
for f in `hadoop fsck / | grep "Replica placement policy is violated"
| head -n3000 | awk -F: '{print $1}'`; do
    hadoop fs -setrep 4 $f
    hadoop fs -setrep 3 $f
done

John