Apologies if this is obvious but I'm yet to receive my kit to delve into unRaid and would prefer to get a plan together now

 

I'll be starting out with just a single solitary 3TB drive which means a parity drive is out. When I get the cash I'll be buying two more and declaring one of those as the parity.

 

My question is whether, considering my first disk will already have data on it, I will be able to just put the 2 new ones in, declare one of them as the parity, and suffer no data loss on the first drive? I would essentially be 'importing' a drive with data on it I guess

 

Thanks

Yes, that's possible, I don't see any problems with doing that, although if I were You, after plugging in 2 new drives I would assign one as parity, wait for it to build and then assign second new disk as data. This probably doesn't matter though.

Excellent stuff, thanks 

Preclear your disks before adding them to a array.  All disks will have to be cleared when added to the array and and any disks not precleared will have it done at that point.  Preclear times on a 3TB drive are more than 24 hours...