# Moving raid disks between two devices?



## zim (Sep 30, 2017)

Hi, need some technical advice, all be it not to do with photography directly I know there are plenty computer tech savvy people here! 

To keep things simple I'm only interested in WD devices and WD red disks!

If I have two WD external hd enclosures both raid 1 can I move the two disks from one device to the other without having them reformatted? By that I mean Install the supported WD drives but not rebuild the RAID disk array.

These are the external HDs
https://www.wdc.com/en-gb/products/personal-cloud-storage/my-cloud-mirror-gen-2.html#WDBWVZ0080JWT-EESN

https://www.wdc.com/en-gb/products/network-attached-storage/my-cloud-pr2100.html#WDBBCL0000NBK-EESN

Hope that makes sense
Thanks for any advice


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## Mt Spokane Photography (Sep 30, 2017)

Most manufacturers let you move a raid array from one NAS to another, its going between manufacturers where they use different software that is a problem.

You would have to contact WD to be sure, or just try. You should have a backup in the event that there is a issue, it can always happen in any event.


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## CSD (Sep 30, 2017)

It's probably safer to migrate the data to a transitory storage system, there's too many gotchas migrating a RAID from one system to another, firmware, software and even controller types can bite you.

This is how I do all my RAID migrations on NAS and SAN solutions. This way you have two copies of the data in flight. If it's on a LAN then copy from over the network, it'll be faster than using a USB type connection. You may also want to enable jumbo packets if your network supports it.


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## Orangutan (Sep 30, 2017)

I'll second the suggestion to contact WD tech support for their advice. Modern RAID implementations are supposed to be smart enough to recognize and reconstruct array configurations (I've done this with RAID1 and RAID5 systems), but I wouldn't bet my data on it.

*Always make backups before moving disks!*


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## bhf3737 (Sep 30, 2017)

Safe bet is that you cannot. The two NAS boxes posted, although from the same manufacturer, use different hardware and operating system. The way that the NAS boxes usually work is that they assign a volume ID to the volume they are creating, by using a combination of hard drive IDs and the system software they use. Any deviation from this, triggers a mechanism to re-build the volume. In this case, even if the hard drives are not changed, the system software would decide that there has been a change and triggers the re-build alarm. Better also check with WD to verify. 
NAS boxes that use FreeNAS system software are somehow interchangeable provided that no encryption is involved.


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## LDS (Sep 30, 2017)

Depends on the RAID "controller" - hardware or software. If your RAID is using an hardware RAID controller, depends if the controller is the same, or at least compatible. If using software RAID, depends on the operating system (usually if the operating system is the same, no problem, but a RAID created say, under Linux won't be readable under Windows).

If your WD enclosures are exactly the same, it should work. Otherwise, unless you are sure about their compatibility, there's a risk the information stored can be damaged. Ask WD.


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## LDS (Sep 30, 2017)

bhf3737 said:


> NAS boxes that use FreeNAS system software are somehow interchangeable provided that no encryption is involved.



ZFS if a very different type of "RAID". It is implemented at the file system level, thereby it doesn't depend on proprietary, lower level implementations.

You can also move encrypted disks across FreNAS systems (don't know about other ZFS implementation, guess FreeBSD ones will work), as long as you have the key.


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## zim (Sep 30, 2017)

Really appreciate the replys,

Yeah this would absolutely be between WD devices. If the answer had been 'no problem' then I'd have considered going cheap and getting barebones later. I didn't go to WD directly because I assumed a slow reply and I'm in a rush but it's a sensible step, I'll give their community a go.

Oh and the consistent advice of backup isn't lost on me!!

Regards


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## kaihp (Sep 30, 2017)

Mt Spokane Photography said:


> Most manufacturers let you move a raid array from one NAS to another, its going between manufacturers where they use different software that is a problem.
> 
> You would have to contact WD to be sure, or just try. You should have a backup in the event that there is a issue, it can always happen in any event.



As usual, Mt Spokane hits the issue right in the center.



LDS said:


> bhf3737 said:
> 
> 
> > NAS boxes that use FreeNAS system software are somehow interchangeable provided that no encryption is involved.
> ...



You can even move ZFS disks between different operating systems without issues (e.g. people have moved ZFS disks from FreeBSD/FreeNAS to Ubuntu/Linux and the opposite way, some have even changed to OS from FreeNAS to Ubuntu and just reinserted the ZFS disks and got the system up & running).

While ZFS is "the best thing since sliced bread in filesystems", it is geared towards large professional deployments. Due to this, I wouldn't recommend OP going for a DIY zfs NAS storage (despite the fact that I run zfs myself).


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## zim (Oct 1, 2017)

Hi,

Just a follow up, got this article

https://support.wdc.com/knowledgebase/answer.aspx?ID=17087

So the answer is yes but as many have said I wouldn't do this without a backup!!

Thanks again for all advice
Regards


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## Talys (Oct 1, 2017)

Here's the thing.

As a hypothetical, if you have the same RAID controller on 2 devices, and they're identically configured, YES. And if things go wrong, it's just RAID 1 (mirror), so at worse, it will take a while to resync the drives -- as opposed to RAID 0 (stripe) or 5 (stripe with parity) where the chances of a problem causing to lose everything is much higher.

BUT: it's not a hypothetical; it's your real data. So who knows what crazy thing could go wrong, and it helps you not at all after the fact to discover that something caused you to lose all your data.

So, my advice: 

OPTION 1: back up your data, move the drives, and if there's any question that it's not running at 100% -- or even if it is -- reinitialize the array, reformat, and restore the data. If it's a two drive mirror, it's probably not more than 4TB anyhow, so just start it when you go to bed, and it should be done when you wake up 

OPTION 2: if your drives run 24/7/365 and are aging, just buy 2 new drives for your target enclosure, initialize them fresh, and copy everything over. I'm assuming these are mechanical, since RAID capable SSDs (or controllers) are super expensive; and if so, they'll be cheap anyways. Your data is worth more than the cost platters! Then take your old enclosure with your old drives, stuff them somewhere safe, and boom, offline backup.


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