Expanding a current lun into a striped metalun is not disruptive to the user. It is done in the background.  There might be a small performance hit but i dotn thin it will be that noticable.
I need to add more space to  a server.  I tried to add a new LUN with concatenate however it errored out saying it had the maximum number of components and to use striping instead.  I've read that striping takes longer  but my question is regarding current users.  Will adding a LUN using striping cause any disruption or latency for users accessing the current drive set?
Mixing Concatenate and striped lun