Adding Device to SDS in 3.6.0.4

I was wondering what the prerequisites are for Adding a Device to an existing SDS in 3.6.0.4. We bought an additional disk for each of our hosts, I can see the disk present in the SIOVM, and I know the process needed however this is the first time I've done it. Does the SDS have to be in maintenance mode during this add or does the ESX host have to be in maintenance mod as well? Just trying to cover my bases without breaking anything.