Originally Posted by jmpage2
Yes, you can continue using the system while the RAID set is being expanded/grown. If you build with Synology Hybrid Raid, you can mix/match drive sizes, and can get an idea of the outcome here;
It has been reported by Brajesh that you cannot add a SMALLER drive to a volume once it is created, new drives need to be equal to or larger than the smallest size drive in the array
heh, forgive me delving into this thread, but I thought I'd just re-emphasise this point. I tired to be smart, buy 2x3tb drives to dump all my drives' content that had been in pc, and then use the drives to bump up the storage on my 1512+ (ie., 3/3/1.5/1/500gb)
Alas, once you've build the RAID with the 3tb, you're stuck, and need to replace with at least another 3tb.
If I would have started with the smaller drives copied to one of the 3tbs, then built the raid, then copied to the NAS from the 3tb, then added both drives into the NAS, I'd have been OK.
Still might do that at some point, but for now I'll just run it as two separate Volumes, not the end of the world, but annoying to say the least that it's not emblazoned in red on the Synology calculator page.