How to setup a second My Cloud Mirror? Copy data from first one

I have a My Cloud Mirror Gen 1 6TB in use.
Some weeks ago I got a second NAS for a low price: Same Type and size, but Gen 2.
I want to use one of both as my regular NAS for my daily work and the other as a Backup system that ist removed from the network most time.
First of all: how to setup the new NAS? My idea: simply remove one of the used hard disk and replace it by one of the new NAS. I expect that the system automatically copys everything to the fresh hard disk. Is this right ?
After that i put the new one back into the new NAS. A new copy procedure will start: now from the first new hard disk to the second new hard disk.
After that all four hard disks should contain the same data. Should it work as described? Are there any things to do for me , exept physically changing the hard disks?

Some month later the daily used NAS will have newer data. What would be the best way to synchronize the backup NAS?

Hi spirit123,

For more clarification on how to transfer the data from the one my cloud to the other you should try contacting WD’s Technical Support.

To Contact WD for Technical Support

The link below will allow you to call support.


Apparently, this won’t work. You must install both old drives in the new NAS for the raid system to work. There is a post on this forum how to proceed from there.

Update on the above comment: I moved two WD red RAID 1 drives from a MyCloud EX2 to a MyCloud Mirror Gen 1. Got the Raid Roaming notification, 3 blue lights, and the system started to rebuild the database. When it finished I got a solid red power light and two solid blue drive lights (data corruption somewhere). Both drives were still accessible, as was the data on them. As it happens, it didn’t matter to me as I was going to rebuild the server from RAID 1 to JBOD with 2 volumes and then reload the data from a second server. But this is a caution of you are going to try this and don’t want to reformat the drives and use a different configuration.

Edit: Everything is working fine now and I have backed up my other server onto the MyCloud Mirror.