Need / Want larger drives on my 3400

[gdsmith56]

My Terastation 3400 has 4x1TB drives.

In Feb16, someone asked "Can a TeraStation be upgraded by the user to a larger set of drives?"
The reply was "Yes but you lose data"

Ok - 1st - what drives can I add? 2TB? 3TB? 4TB? (or not that I could afford them)--> 6 or 8TB drives ???

(I am RAID5 configured) I vaguely remember reading that I could do a 'hot swap' (or for me, full shutdown, replace drive, reboot) of ONE drive with the system.  If, for example, I hot swapped with a new 2TB (or larger) drive, it would work but would only recognize 1TB of the space. (I guess the other TB is lost/ignored).

So - my question is If I do one drive at a time, every two days (recovery/rebuild/etc time), what do I have when I finalize the fourth new drive? 

Stats: 4x1TB drives, configured for RAID5, giving me approx 2.8TB of space.  I am currently sitting at 2.8TB minus a few gigs (i.e. FULL !!!) and am having no problems with any part of the system.  Firmware is up-to-date.

[Texturtle]

If you swap the drives one at a time and let the RAID rebuild you will end up with same size array you have now. The reason is that the parity stripe has to remain consistent across all drives so the amount of data on each drive can't change. The only way to increase the size of the actual array is to delete the RAID 5 and create a new RAID 5 array on the new, larger drives.

The TS3400 will recognize drives up to 4TB for sure, maybe larger but it hasn't been tested to my knowledge.

The best procedure is to delete the array, then replace 3 of the four drives. Bring the unit up and format the new drives, then replace the remaining drive and format the new one. Once you have all 4 new drives in the NAS and formatted create a new RAID 5 array. That will give you usable space equal to the space of 3 drives. With RAID 5 you will always use the equivalent space of one drive for parity.

[gdsmith56]

The one step that you left out, before 'replace 3 of the 4', is BACK-UP the 2.8TB of data that is currently on the 1TB drives.

And I have nothing that will hold that much data - guess it's time to buy one of the larger external drives.