Question Getting NAS ready?


Standard Member
I currently have a 24TB WD MyBook Duo. I believe there are 2 x 12TB WD Red Hard Drives in it.

I currently use 13TB of space and I am operating RAID0. Obviously this is not ideal as if one of the hard drives fail, I'm in big trouble.

So I've been searching NAS enclosures with the ability for a bigger capacity (with the added benefit of network access).

My question is, if I buy a 4 bay enclosure, with another 2 x 12TB drives, I want to also put the existing 2 x 12TB drives in it (with the existing data on it) to give a total of 48TB. Then, I want to convert this to RAID1. Total then would be 24TB but it would all be backed up.

Is that possible? Can I convert the existing two to join a RAID1 setup without losing the data?

Also, would Red drives be good for home streaming if I attach the NAS to my wireless router via Ethernet?


Well-known Member
To partly answer. If you put the drives from the duo into a nas, the data will go as the disks will be formatted.

Put the new disks in to the nas, setup, then copy from the duo via usb or network to the new disks.
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Ross Martin

Standard Member
I have a Synology DS1618+

What i did was i removed the drives it came with and it ran a full surface scan on each disk. It can take days to do this but i like to be extra sure! Once done the disks were put back into the NAS and on a Synology it will default to using the SHR for RAID with two disks it will effectively RAID 1 them.

12TB disks in a RAID 1 will give your roughly 11.1TB of usable space.

If you were to put your existing 12TB drives from your WD MyBook Duo into the Synology NAS it will format the disks so you will use your data. It does this because the disks are from a foreign system so the infomation

I would be inclined to do a full surface scan on your old 12TB disks as well.

With all four 12TB disks SHR will default to using redundancy so will give you a RAID 5 array (using SHR) this will give you roughly 33.5TB of usable space.

I use my NAS and WD Red drives to stream full 4K rips to my TV via a Nvidia Shield and Kodi and it works fine. I have no issues what so ever!

I hope this helps!


Well-known Member
Total then would be 24TB but it would all be backed up.
You'll have redundancy at least.

Put the new disks in to the nas, setup, then copy from the duo via usb or network to the new disks.
Individual drives are 12TB - space required is a minimum of 13TB
New drives will have to go RAID0
Adding original drives will then require RAID0+1 migration.
You'll have no back up if you use the existing drives during this migration.

Can I convert the existing two to join a RAID1 setup without losing the data?
My single experience of WD MyBook is that they use mdadm to provide the RAID.
I was going to say yes but looking at mdadm --level it doesn't mention 0+1.
The conversion might be fine on a vanilla linux system (if it's possible) but a NAS will just reformat the disk if it doesn't recognise it.

A Raid1 to Raid10 conversion but you want Raid0 to Raid0+1.

Sloppy Bob

Distinguished Member
I'd say for a NAS with media on it, RAID1 is overkill.

You're halving your NAS capacity and still leaving yourself vulnerable. You're spending a fair bit of cash on the NAS and 2 more drives and gaining 0TB of space.

RAID isn't backup. It's redundancy.

If your NAS fails, if it breaks down, if it gets lost or stolen you have no backup.

If you delete something important from it, you've deleted it from both copies using RAID1, you don't have a backup.

IMO, if you want redundancy, you'd be better using RAID5 giving single disc redundancy and keeping your current WD MyBook as your backup.
Or.... even better IMO. Buying a Synology NAS and using their own SHR1 which gives single disc redundancy like RAID5 but also gives you the option as time goes on of upgrading to larger discs without wasting space.

As noted by the above posters. As soon as you slot a disc in the NAS it's going to get wiped.


Distinguished Member
In standard RAID levels, RAID 1 does not imply only two discs - it can span as many as you like. So potentially you could put four discs in a NAS, tell it to configure them as RAID 1 and it'll mirror across all four yielding 1/4 of the storage volume usable. Needless to say, RAID 1 is rarely used over more than two discs, but it could be.

I've no idea what SHR would do, but I suggest you check the manuals carefully.

Wik'i's articles on "standard" RAID levels are a fairly good primer.

+1 to RAID (whatever version) is never "backup." Backup means availing duplicate copies of the data "somewhere else," RAID does not do that. RAID is (mostly) used to avail continues access to data when a disc dies (they all die in the end) and some versions of RAID (such as RAID 0) don't even do that. RAID 0 is mostly a way to have bigger volumes than the discs allow by spanning across multiple drives, though it can have some performance benefits (though it's arguable whether it makes much difference to a media tank.)
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Sloppy Bob

Distinguished Member
SHR1 is effectively RAID 5. It's single-disc redundancy. (There's also SHR2, two-disc redundancy for the truly paranoid)

The main difference, which is beneficial to a NAS for media is you can mix and match drive sizes and using larger discs, expand the volume.
With RAID 5, once you stick your first disc in, you stuck with that size of disc, regardless of buying larger ones, the extra space will be wasted. Using SHR you get full use of your discs, if you follow a few basic rules.

For example, I have an 8-bay Synology for a media server. I figured I was cheaper buying the 8-Bay and using my current discs than buying a 4-bay and having to buy the largest size drives I could at a premium rather than the best price per GB discs.
I'm so glad I did that as if I'd bought the 4-bay I'd have ran out of space in no time at all.

All the discs in that were 2TB,3TB,4TB and 6TB to start off with, I got complete use of all the discs and then when I started running out of space and over time some disc failures, I just bought larger discs and expanded the volume. I now have 2x8TB and 6x10TB in it and am looking at an expansion module.

I don't think SHR is the ideal choice for mission critical business use, but for a Media NAS it's perfect.

NOTE - I have a 2nd NAS as a backup with all my older, smaller discs in it.
Why do I have a 2nd NAS. Because....

RAID isn't backup, it's redundancy.... :p
And I really can't be bothered ripping the thousand plus movies I have on my NAS again and the TV shows and the old stuff that probably got disc rot by now and I'd have to buy it again and ...........
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Well-known Member
I don't use RAID on my 4-bay NAS. To me, it's unnecessary and wastes too much space. All my data (movies/Music/Photos etc.) is backed up to external drives (some important data like photos/family videos to more than one drive).

If a disk fails, I'll just chuck a new one in and restore from a backup (hopefully)!

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