Upgrading hard drives

[Enquiries]

I have a DS918+ currently set up as SHR1 with the four bays each populated with 2tb hard drives. I want to replace all four drives with larger cpapcity drives. Do I replace each one individually and how do i ensure that the 2tb drives can be resold without any security issues re my data`?

[Ekky]

You can replace the drives one by one to upgrade the capacity. Just make sure to follow the steps in the DSM (DiskStation Manager) to do it safely.
As for selling the 2TB drives, the best way to ensure your data's security is to wipe them clean before selling.