How much does a drives RPM make a difference?

iProb8 wrote:
I currently have both NV+ units decked out with 1.5TB 7200 RPM Seagate drives (Seagate ST31500341AS). I'm starting to run out of space on the primary unit and considering upgrading it to four 2TB units.

It does not seem that "economical" to replace all 4 (presumably otherwise "good") drives with 4 drives that are only 25% bigger. You currently have 4.5TB usable, so your new would only be 6.

What about shifting to 3 x 3TB drives? That will give you the same 6 usable -- still leaving one slot for a future 3TB drive at, presumably, a lower price point.

Assuming you have someplace to temporarily store 1.5TB of data, or if you have at least 1.5TB "duplicated" on your 2nd NV+ or a different source... If you bought 3 drives, it would be easy (but slightly time-consuming) to transfer your data:

1) Ensure at least 1.5+ TB of data is backed up to other "random" drives or on NV+ #2
2) Put #1 3TB drive in external USB case. Back up remaining up-to-3TB from NV+ to that drive.
3) Shutdown NV+, remove all drives, label them 1-4
4) Insert #2 & #3 3TBs into NV+. Update to latest firmware. Create new X-RAID volume
5) Restore #1's data to NV+
6) Insert #1 as the 3rd drive in NV+
7) After expansion, recopy the remaining 1.5+ TB from scattered random drives or the other NV+

--> Note, if desperate, you could yank one of the 1.5TB's from the NV+ at the start (MEANING YOUR ARRAY IS DEGRADED), put that in a USB, to store 1.5TB's of your original data - then complete the backup with one of the new 3TBs.

Sounds complicated, but this buys you a new array with latest firmware (I know with the Pro's, you need to recreate the array with the latest firmware to expand beyond 15TB?) and still have room to add 3TB more of space via the 4th drive.