"You're not alone, Dave! RAID rebuild on my Drobo takes about 8 hours with two 1.5 TB drives and one 1 TB drive. And slow interfaces and random access don't help - I'm only getting 25-35 MB/s on my Drobo and Iomega ix4, meaning it will take more like 12 hours to copy a single terabyte of data. Raw USB or FireWire enclosures might do somewhat better, but there's a massive risk of data loss with single-drive units, something I'll be writing about soon. My advice is to buy a Drobo. It's not all that fast, and it is expensive, but it allows you to have a protected place to put your data that you can upgrade as time goes by. Need more space? Pop in another drive and let it do the work. No migration required." - Stephen Foskett