Upgrading storage - ReadyNAS 314

[jtaustin]

I have 2x 3TB hdd configured as RAID 1.  I want to upgrade capacity and change to RAID 5.  What's the easiest way to do this?  I do not take backups currently, so backup/restore would have to be a one-off solution.  Thanks!

JT

[Marc_V · Accepted solution]

@jtaustin

Welcome to the Community!

Since you have 2 bays available, if your array is configured on X-RAID then easiest way would be to add a 3rd disk to your NAS, this will automatically expand your volume and change your RAID to RAID5 just like what you want to have and since you only have a single volume RAID1 If you are currently on Flex-RAID you can change it to XRAID then expand.

Please see the following links below that might help and provide more information.

What is XRAID

What is Flex-RAID

Changing to Flex-RAID to XRAID

HTH

Regards

[Marc_V · Accepted solution]

@jtaustin

Welcome to the Community!

Since you have 2 bays available, if your array is configured on X-RAID then easiest way would be to add a 3rd disk to your NAS, this will automatically expand your volume and change your RAID to RAID5 just like what you want to have and since you only have a single volume RAID1 If you are currently on Flex-RAID you can change it to XRAID then expand.

Please see the following links below that might help and provide more information.

What is XRAID

What is Flex-RAID

Changing to Flex-RAID to XRAID

HTH

Regards

[jtaustin]

@Marc_V That's awesome!  It is running X-RAID.  Are there any restrictions/guidelines as to the type/size of drive I add next (like mixing hdd/ssd)? I'm assuming it will choose the largest drive for parity?

Unrelated, but I've had such a good experience with this device over the past 4 years, I'm really surprised that Netgear doesn't come up on more "best of" lists.

[StephenB]

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@jtaustin wrote:

I'm assuming it will choose the largest drive for parity?

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No. Standard RAID-5 / XRAID doesn't have a dedicated parity disk.  Parity blocks are spread across all the disks.

You need to add a drive that is at least 3 TB.  If it's bigger than that, the extra space will be wasted until you add another disk of the same size (or replace a 3 TB drive with the larger size).

I suggest hot-inserting the drive.  We always recommend making a backup first.

Netgear will give you a warning if you mix speeds (5400 or 5900 with 7200 rpm).  The array will still work.

You can mix/match vendors (for instance, WD Red and Seagate Ironwolf).

[516-Andrew]

Note one subtle point made: Same size, or larger. You cannot add another smaller drive in xraid. Xraid does not like that. (It just told me.)  I have 2 3TB's mounted as xraid-1, and I came by 2 2TB drives I was just trying to utilize. These cannot be added unless

a) I back-up all, reformat the volume with all drives installed, and then restore.

b) I turn off X-raid {which then makes it Flex-raid), and then I can mount a second volume with these drives as a raid-1, and deal with having two volumes - also losing the automatic features that X provides, mainly popping out a drive and popping in a larger one on the fly (there is no add, as I would already be at 4.)

     I haven't decided which yet... 3+2=5TB (and accepting losses), or 2+2+3+3-3=7TB, and doing work...

Not sure if external drives are set up the same way. (You can somehow add 5x 4TBs to each available interface, for another 40TBs.)

[StephenB]

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@516-Andrew wrote:

Note one subtle point made: Same size, or larger. You cannot add another smaller drive in xraid. Xraid does not like that. (It just told me.) 

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Correct.  In your case it would need to 

1. shrink your current volume down to 2x2TB RAID-1 (leaving 1 TB on each disk unused)
2. expand that volume to 4x2 TB RAID-5
3. add a new 2x1 TB RAID-1 group on the 3 TB drives
4. concatenate that RAID-1 group to the RAID-5 array.

The first step is the problem - XRAID already does steps 2-4. But shrinking the current volume only works if there's enough free space in your existing volume hold your data.  And the sequence is quite a bit more complicated if you'd already expanded your array in the past. 

Personally I think they were wise not to attempt it - it often can't be done, and it would be very hard to explain why.  Though it would be useful to allow folks using FlexRAID to shrink a RAID group manually.

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@516-Andrew wrote:

     I haven't decided which yet... 3+2=5TB (and accepting losses), or 2+2+3+3-3=7TB, and doing work...

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Or just buy a 3 TB drive (WD30EFRX or 3 TB Ironwolf) for $90 or so, and don't use the 2 TB drives.  Spending money but doing no work. 

There is a third option with flexraid, which is to create 3 volumes (using JBOD on each of the two new disks).  Then you'd have 7 TB of storage, but you wouldn't have any RAID protection on the two new ones. 

FWIW, the main downside with having multiple volumes is it's a bit harder to manage free space.  Occasionally you need to shift shares around to maintain adequate free space on each volume.  That can be a bit tricky if you are using smaller disks (as you are).

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@516-Andrew wrote:

Not sure if external drives are set up the same way. (You can somehow add 5x 4TBs to each available interface, for another 40TBs.)

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You are thinking about the EDA500 expansion chassis - which was discontinued some time ago.  XRAID worked the same way on the expansion chassis - but you'd have one volume per chassis.  The issue was that the SATA connection between the NAS and the chassis was a bottleneck, so some operations (expansion and resync) were both very slow.

But perhaps more importantly - your comment makes me think that you might be under the impression that your NAS is limited to 4 TB drives.  It's not.  You can put in drives up to 16 TB if you want.  And as larger drives come out, you should be able to use those too.  There is no known limit on the size of the disks that your NAS will accept. 

However, the time to resync the array (as well as defrag, balance, scrub, etc) goes up with the volume size, and at some point it becomes unwieldy.  Also the RAM in your NAS will limit how much it can handle.  But you could certainly go larger than 4x4TB if you want to.