500GB a day down a 100mb/sec pipe is a lot to push.  Remember that a lot of
database activity takes place comparing a client file system and what server
database says its last backup was.  I would expect 500GB (4000Gbits,
4000000mbits) to take a while.  Say about 12 to 15 hours at best.  Do the
math.  A gigabit connection to your switch may help you.  Now, the database
is also important to reorg.  The other piece is the numbers of files in the
file systems have an impact on the time.

Based on numbers that I have heard, you are looking at as much as a day.  It
depends on your disk subsystem speed.  Just be cause it is EMC does not mean
it is fast.  It must be laid out properly and not all EMC disk is created
equal.