ReadyNAS NV+ v1 and HDD's management/upgrade

[Blooky]

Hi

I have a ReadyNAS NV+ v1 (RND4000).

At the beginning several years ago, I bought and used it with 2 HDD's. (WD10EARS, Western Digital "Green", 1Tb 64mb 5400rpm)

I recently decided to add one HDD (HUA723020ALA641 - 2Tb 64mb 7200rpm), and the same second juster after. (Since the max size of HDD's I can put in is 2Tb)

The features I need seems to work nicely and the 2x HUA723020ALA641 are great, then I am considering to continue replacing the 2 first/old WD10EARS by two other HUA723020ALA641 and then the 4 Hdd's will be HUA723020ALA641.

So, The 2 first slots are used by 2x WD10EARS and the 2 lasts by 2x HUA723020ALA641.

=> What's the process to replace them then without losing data ? 

Thanks in advance for your advices and help !

[Blooky]

One mistake, the Ols HDD's are WD10EADS, still Western Digital Green, 1 Tb but 32mb only.

[Sandshark]

While properly upgrading the drives shouldn't cause a data loss, nothing is certain.  It's best if you make a backup first.

But the procedure is simply to remove one and insert the new one in its place with the power on.  Once the re-sync is complete, do the same with the other.