Yes, it is designed to be done online and is non-destructive.
I have a PowerEdge R530 with Perc H330 mini with currently 3, 300GB sas hard drives configured as one virtual disk.  VMWare ESXi 6 is installed with a couple virtual machines running and I am out of room.  I have installed an addition 3 of the exact same hard drives and would like to expand the virtual disk with 2 of the drives and set the other as a hot spare.  Using OMSA I set the hot spare easily, however before I reconfigure the virtual disk, please let me know if I am doing it correctly. From within OMSA, 1) select my virtual disk and select "reconfigure" and execute 2) check the two additional drives  to add to the virtual disk and press continue (step 1 of 3) 3) switch raid level from the default Raid-0 to the current and desired RAID-5 and press continue (step 2 of 3) 4) verify settings and press finish (step 3 of 3) I can do this without shutting down my VM's right?  This will not destroy my data will it?  I have backup, but would prefer not to have to restore. Thank you for confirming or pointing out my mistakes ahead of time. 
PowerEdge R530 - Expanding Raid 5 by adding disks