Rate of synchro speed

I would like to know how open-e has setup the synchronization rate if they can't control the link speed of every client , this is the link to DRBD manual that explain how we need to calculate the synchro speed of DRBD system , how open-e manage this? To be setup correctly we need to know exactly the speed of disk subsystem and network bandwith between each node but open-e doesn't give us any tools to measure it ( like hdparm and iperf )

Link : http://www.drbd.org/users-guide/s-co...-rate-example2

Open-e uses IO Meter to get their results http://www.iometer.org/ because not all hardware performs the same.

You can also check it test.log look for hdparm -t /dev/sdb to check you speed