it's possible to expand an existing array if you are not exceeding its specs (these days with 25 drive DAEs) you can have a lot more slots than your model will actually support.
other questions come up is what flare you are currently running, are you using traditional raid groups versus pool, drive types and protection. Can you give us more details ?
Sorry for disapperaing
We have only one storage pool consisting of 20 disks, RAid type: RAID5. No Raid Groups.
We got 5 new disks to fill VNX two shelves completely to full capacity.
Do I understand correctly that I just need to insert these new drives, then in Unisphere expand exisiting Pool with all 5 drives, and start using them? Will pool expansion affect other 20 drives in production?
I am new to EMC