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[JP]

I initially put only a single 1TB (samsung) drive into my DNS.  I want to now add another for redundancy, but I can't buy a 2nd, identical to the first, 1TB samsung drive (not sold anymore).  Can I put in any other 1TB drive into the 2nd bay?  Will the RAID functions work? What if they're of different capacities (e.g. the new, 2nd drive is 1.5TB).

Can I setup the backup w/o loosing my data on my original drive?

Thanks!

[gunrunnerjohn]

The RAID functions should work with a different brand, I've never seen anything to indicate that's ot possible.  There was a recent thread here that stated you could convert to RAID-1 by adding a disk without losing your data.  I'd have a full backup of the contents of the DNS-323, which you should have anyway...

[fordem]

First - I note that you ask ...

Can I setup the backup w/o loosing my data on my original drive?

I want to make it very, very clear - RAID1 is not a backup - and even with a RAID1 array you will still need to back up your data.

To deal with your questions - the DNS-323 will work fine without having identical drives, you can use any brand or model of drive provided it's capacity is the same as, or larger than the first drive - this is very important, it is possible for one drive to be described as a 1TB drive and have a capacity of perhaps 983GB (I'm just pulling figures out of the air here) whilst a second drive also described as 1TB might have a capacity of 979GB - if the drive you started out with was the 983GB one, you could not create a RAID array using the 979GB one - BUT - if things were the other way around, there would be no problem.

If you were using a 1TB drive as the original and a 1.5TB drive as the new one, you would obviously not run into the problem I just described.

Depending on the firmware version in use - I believe this was introduced in either 1.05 or 1.06 - when you install the second drive, the format screen will have a check box that you can check to have it create a RAID1 array, what should happen is that the system will create a 1TB partition and format it and then sync the two drives to give you a 1TB RAID1 Volume_1.

It should also configure the remaining space as Volume_2 - however I have not personally tested this - I have created RAID1 arrays with drives of unequal sizes and know that this is what happens if the array is created with both drives in the system, and I have also tested adding a second drive to the unit and creating a RAID1 array with drives of the same size and I know that that works also.

Now - what I also know from experience - is that if you have a RAID1 array with a JBOD Volume_2 as described above, and a drive fails, when you replace that drive, and the unit successfully recreates & resyncs the RAID1 array, the JBOD Volume_2 is lost, so - I would not be very surprised to discover that creating a RAID1 array "on the fly" with a larger disk does not result in the expected two volumes - if I find the time, I'll test this and see what happens.

[gunrunnerjohn]

First - I note that you ask ...

I want to make it very, very clear - RAID1 is not a backup - and even with a RAID1 array you will still need to back up your data.

Hence my suggestion that he have a backup first. 

[fordem]

The danger in suggesting that he backup first, is that it does not emphasize the need for an ongoing backup - hence my re-inforcing your suggestion 

[gunrunnerjohn]

Good point,

Data you don't have at least two copies of is data you don't care about! 

[fordem]

Please make sure the two copies are not on the same piece of media or drive  - yes - I have seen it happen. 

[gunrunnerjohn]

Please make sure the two copies are not on the same piece of media or drive  - yes - I have seen it happen. 

That should go without saying, but sadly you are correct. 

[hilaireg]

... unless of course, JP is also a professional gambler who rarely loses (1:10000).  JP and others, if you're not blessed with such luck ... BACKUP your data BEFORE any upgrade operation.

There have been numerous "horror" posts in the DNS-323/343 forums about loss of valuable data ... ensure that you heed all of 'fordem' and 'gunrunnerjohn' advice.

Cheers,


@fordem

Nice to see you're still around helping members.

[gunrunnerjohn]

In addition, RAID is not backup.  If an errant application or simply a careless finger deletes network files, they are GONE from both RAID volumes.

[JP]

Thanks Everyone for your responses.

I'm a bit surprised to hear that two drives in a single NAS is an insufficient backup! I suppose if the box were to die itself and take the drives with it, that could be an issue. So what is the best way to backup?  A backup NAS for the backup NAS?

[gunrunnerjohn]

Think about it.  If you erase a file by accident on a network drive, it's gone.  It's gone from both RAID drives, because that's what you asked for!  If you point to a folder and hit delete, the whole folder is gone.

Is that sufficient backup for you?

Let's say you're not making the mistake, however an errant application or malware is trying to erase or scramble the data?  Same result.

RAID of any level is NOT backup, it's simply a means to insure data availability for a single point hardware failure.