Format or Migrate

Newbie Here Asking For Advice Again Please.

I have the EX4100 with 2 x 6tb discs set as raid 1 which is now full.

I have all 6TB of data backed up.

I have just bought 2 more 6TB discs to fill the bay, and will now set to raid 5 to give me 18TB of space.

My question is, will it be quicker to format the two drives already in, add the two new drives, choose raid 5

and then reload all my data?

or just add the two new drives and migrate to raid 5?

I’ve been reading on the forum about the time it takes to change to raid 5 and also the problems of freezing.

Any advice would be really welcome,

Thanks In Advance.


This will depend on your needs, If you rather start fresh you can reformat and copy the files, however you can change to RAID 5 and migrate, this option allows you to use the drive while the unit is still working, the unit will be slow as it is migrating, but you can still access the files. 

Thanks for the info,

Bit the bullet and chose to migrate.

I read it could take 2-3 days to complete, but it is slowly coming along, showing 30% done after about 15 hours.

As you say, I can still access the files while it is migrating.

Thanks again for taking the time to reply

Finished after 32 hours with no problems, which was a lot quicker than I thought.


Sorry to re-awaken an old thread but thought you might know the answer to this. I am in a similar position to where you were at the time. I have 2 x 3 TB drives configured as a RAID1 mirror and just bought another 2 x 3 TB drives and am wanting to migrate it to a RAID5. I cannot for th life of me see the option to do a migrate of the data. When I go into the RAID setup it only has the option to do a change RAID mode and from all accounts I have read doing this is destructive. Do you remember if you did anything special to bring up the migrate option ?

Also both HDDs are coming up with Red LEDs at the moment but assume that is due to not being in a RAID set. THe Dashboard itself is reporting the drives as Healthy as is the SSH interface when I look at the properties (but for some reason the new HDDs are sda and sdb and rather then sdc and sdd).

Anyways any tips or points from anyone would be great :slight_smile:



Hi JediNite

I did migrate and had no problems. Turned out to be a lot quicker than I thought.




But where in the Dashboard did the option come up ? I’ve not been able to find it. Did you go into the RAID and then Change RAID mode and there were options in there to do either a full change (ie. delete and rebuild from scratch) or a migrate ?



Hi JediNite

I can’t exactly remember as it was a while ago.

But I think it came up when I changed Raid Mode to Raid 5



No probs… I’ll wait for the backup I am doing of my current data to finish and then give it a crack… It is a shame the doco from WD is not more helpful…

Thanks for your help :slight_smile:



Hi all

Well I finally took the plunge on this last night and it has not gone well. I did find the options in the web GUI in the Change RAID mode section so ran this. The time on the resync was going to take 72 days initially but got in with ssh and tweaked some kernel parameters and got it down to 6 hours. Checked it this morning and my array was still a Raid 1 instead of being converted to a 4 drive Raid 5. I checked the parameters that diskmgr was run with and according to the help it tried to convert from normal volume to Raid 5 instead of from Raid 1 to Raid 5 so this probably explains that.

I then tried to do a volume expansion also via the Change RAID mode interface and now the NAS is in a loop where it wants me to swap and replace drives even after a reboot. Not sure how to get it out of this loop but planning to log a ticket with WD.



Went to log a ticket and of course the WD support site is not allowing me to do so. Internal Error 26575804. Anyone got any ideas at all ?

Gave up trying to log a ticket when it failed a few times. I’ve since blown away the volume config and rebuilt it and recopying back the data… Slow process, but at least the NAS unit itself will be happy with the config and the data will be consistent :frowning:

Not happy WD…