RFSU, You can not expand the Virtual Disk on a VRTX, it's not a listed option.  It was supported on previous systems but was excluded on the VRTX. You would need to backup the data. Reconfigure/Resize the arrays, then restore the data back to the arrays. Sorry about that. Let me know if this answers your question.
I'm trying to expand a virtual disk in VRTX chassi. I have a RAID6 virtual CSV disk that needs more space but I cannot understand how to achive this in CMC. The only option I can find is to assign a hotspare.  Any ideas?
VRTX expand RAID