Because I build VD from VD MGMT (CTRL-R), I delete VD1 (backup first data on VD1) from VD that MGMT Screen. After that I open OMSA, and Virtual Disk, Recontruction task can be chosen on virtual disks. and Click Physical disk I want add, choose Raid 6 and Finish. State Become Recontructing. Thanks. 
I have Dell Power Edge R720 with RAID 6 with 5 Harddisk. Virtual Disk 0, Size 1,843 Gb Virtual Disk 1, Size 949,80 Gb. I want to add 1 new Harddisk, condition has ready.to Virtual Disk 1, Can I Add 1 Harddisk to Virtual Disk 1 ? I dont want Virtual disk 0 delete too. My OS using VMware ESXi 5.5 and I using OMSA.  Thanks  for your help...
Add Harddisk on Dell Power Edge R720 with RAID 6