Help deciding RAID5 v RAID1 - archival purposes

[nanofrog]

awsome! we finally have an answer of sorts!!! the 4 bay will have lots of expandability for me. im probably going to purchase 2x2TBs or 2x1.5TBs to start off with in RAID1 mirrored mode. then when i save up a bit more hopefully the 2TBs will have come down again.

That unit does offer you options. I'd just avoid it's RAID 5 setting, as it's a software based system, and doesn't have the ability to handle the write hole issue with parity based arrays.

its not possible to expand RAID1s is it? you have to copy off, format, then copy the data back on? easy enough to do!.

No. RAID 1 is meant for 2x drives, and you get half the total capacity. To gain additional capacity, you'd want to switch to a level 10 array (make a pair of RAID 1 arrays, then stripe the two sets together). You end up with additional capacity, and redundancy is also improved.