I have 3x 3TB Red drives setup currently and have purchased an additional 6TB Red. I have removed the 3 3TB and put the 6TB but format is grayed out in utilities.
Will I be able to use the 6TB along with the 3TB or not because it isn’t the same size?
Yes, you can use the 6 TB in JBOD along with the 3x 3TB Red drives. Also, what is the RAID configuration of the my cloud?
RAID5. Any idea why the format button is greyed out?
Maybe you should try contacting WD’s Technical Support about this.
To Contact WD for Technical Support
The link below will allow you to call support.