Changing hard disk in My cloud EX4

I bought a 4 To hard drive in order to replace my 2 To hard drive present in bay number 1 of my cloud EX4.
All the other bays are each occupated by 2 To hard drive.
Should I just exchange the hard drives and then boot my NAS or is there something I should worry about before this operation ?
I worry if i’ll loose the OS of the NAS or data on the other drive
Thank you

Hi @o.djaafar,

Please refer to the following KB article: Replacing an Internal Drive on a Multi-bay My Cloud