Might want to take a look at EASEUS Partition Master.
EaseUS Partition Master Unlimited Edition is an ALL-IN-ONE partition
solution and reliable PC & Server disk management toolkit, especially
for large enterprise users. It allows unlimited usage within your
It covers all the features of EaseUS Partition Master Server Edition
and brings together flawless hard disk management for Windows Server
2000/2003/Home Server/2008(R2 SP1 included) and Windows
2000/XP/Vista/Windows 7(SP1 included)/Windows 8 on MBR and GUID
partition table (GPT) disk including: Partition Manager, Disk &
Partition Copy Wizard and Partition Recovery Wizard.
A little bit more expensive, but our company recently re-partitioned all of our servers. using it. Performs the repartition with out having to power off the server, then a simple re-boot is necessary to commit the changes. Doesn't take very long at all. No data loss whatsoever, however you always want to back things up.
Gparted is nice because it is free and it does work, but downtime is involved.