Upgrade MyBook World II 2x1TB to 2x3TB

Hi guys,

After hours of researching if it’s possible to upgrade the MyBook World II with bigger hard drives i finally just tried it.

Around one month ago i bought a MyBook World II 2x1TB and ordered two WD 3TB Caviar Green SATA drives.

I did not have any data on the drives, so if you already have data on your drive it would be a good idea to backup them somewhere else. But no panic, if the upgrade won’t work you can still use your old drives… but your data on the drives will be lost.


Drive A = Original 1TB drive in bay A

Drive B = Original 1TB drive in bay B

Drive C = First new 3TB drive

Drive D = Second new 3TB drive 

  1. Update to latest firmware

  2. Reset to factory

  3. Power down & Exchange drive B with drive C (first new 3TB drive) 

  4. Power on & do a Factory reset

  5. Check if the MyBook boots and is working (reachable through the web interface etc. )

  6. Power down & Remove Drive A & C

  7. Put drive C into bay A

  8. Put drive D into bay B

  9. Power on and do a factory reset

  10. You should have a new 2x3TB WD MyBook World II now

If this is not working for you, you can still Remove drives C & D and put back A & B.

The MyBook World should boot as normal.

Some notes for compatibility and product warranty:

In some forums and communities you’ll find the answer that this procedure is not supported and it’s not allowed to put larger drives into the MyBook World. My experience was that it works, anyway, the product page of MyBook World says:

“[…] Want to upgrade a drive? Simply open the case and replace the existing drive […]”

Which includes the word “upgrade”… In my understanding this procedure shouldn’t void the warranty if you’re using WD CaviarGreen drives.

1 Like

Cool!!! =D

Hi there

Interesting. I was thinking about upgrading, too. However, my NAS is pretty full, and backing up to another drive would be expensive (buy drive…), time stealing and annoying. So I am wondering, if there is no other solution. This is an idea, and I am wondering, if somebody could comment on that to confirm or deny its a working solution or correct the procedure to make it work.

Condition: The NAS has two 1TB drives and is configured to RAID 1 (Mirrored) (and it is currently about 3/4 full)

Step 1: Power down drive using the “on/off” button.
Step 2: Remove drive in Bay B
Step 3: Power on
Step 4: Configure the drive to the RAID modus “JBOD (Just a Bunch of Disks)”
Step 5: Power down again and put the new drive in Bay B by a 3 TB drive
Step 6: Power on using “on/off” button
Step 7: Format new drive
Step 8: Copy all data from the old drive in Bay A to the new drive in Bay B
Step 9: Power down
Step 10: remove old drive in Bay A

Step 11: Power on.

Step 12: Change configuration to RAID I (mirrored)

Step 13: Power down, put the second new 3 TB drive into Bay A
Step 14: Power on

So, of course, the big question is: WILL this NAS automatically take the data already stored on one new drive as the “master” data and mirror everything to the second new drive?

So again: This is JUST an idea, a plan, do not apply it until nobody confirms it works!!! Is there somebody who can  comment on that and confirm or deny, that its a working solution, or correct the procedure to make it work???

Thanks for any helpful answer!


I’ve read an article about upgrading and keeping your data but don’t remember where it was.

First of all: Don’t switch the RAID mode when you got data on your drive.

The guy in the article desribed it like this: (RAID 1 mirrored setup)

  1. Remove drive B and put the bigger drive into drive B

  2. Switch on and wait for the successful rebuild of the raid (data are copied to drive B - this will take some hours)

  3. Switch off, remove drive A and put the other biger drive inside bay A

  4. Switch on and wait for rebuild (data are copied to rive A)

  5. Login with SSH and resize the RAID to 2 TB

  6. done

Another solution would be:

  1. Buy a USB to SATA Dock or external harddisk enclosure (~20 €)

  2. Remove your old drives from your WD and put one of them (e.g. A) inside the hardisk enclosure // USB SATA Dock

  3. Put your new drives into th MBWE

  4. Reset and try to boot MBWE

  5. Configure the new disks as you want

  6. Connect your old drive inside the SATA/ USB bridge with USB and copy the data on the WD MyBook World

I didn’t test any of these solutions, but i think this should also work…

RAID 0 (strip) is NOT upgradable without lossing data. You should backup you data first and then the upgrade. I am in the same situation. As anohter reader confirmed upgrading to 3T, I will repeat this expertiment and will provide the update. BTW RAID ) **bleep** on WD. Should always use RAID 1. 

Yes, you’re right, with a RAID 0 (striped) setup the Upgrade is only possible with the loss of data / backup to another harddisk / device.

BTW , you should always have a backup copy of your data.

I’m looking forward to your report of success or any problems you might have…


Something off topic:

“[…] Should always use RAID 1.” sounds weird…

RAID 1 (mirrored setup) is NOT a backup strategy. You should use RAID 1 if you need your data 24/7 even if there is a hardware error. It will not protect you against data loss, file system errors, device failures, firmware bugs or layer 8 problems :wink: