ReadyNAS Ultra 6 Plus.... 18TB -> 24TB

you can't expand past 16tb.

you can't expand more than 8tb from your original volume size.

Wed May 7 09:04:35 EEST 2014 Data volume has been successfully expanded to 15740 GB.

it looks like your hitting (or about to hit) the 16tb expansion limit.

I would think your only option now is to backup everything (ideally to a different nas), then factory reset the readynas with all 4tb drives installed.

you could also consider converting over to OS6 (see thread, it is not supported by netgear but is possible), this of course also requires backing up all data first.

viewtopic.php?f=51&t=70133

I believe the plan was to go from 6x3TB dual redundancy (12 TB volume) to 6x4TB dual redundancy (16 TB volume). Original info was that the 6x3TB was the starting point.

If all that is correct, then OP hasn't hit either expansion limit. Of course if the original install was actually done in stages he might be hitting the 8 TiB growth limit.

StephenB wrote:
I believe the plan was to go from 6x3TB dual redundancy (12 TB volume) to 6x4TB dual redundancy (16 TB volume). Original info was that the 6x3TB was the starting point. If all that is correct, then OP hasn't hit either expansion limit. Of course if the original install was actually done in stages he might be hitting the 8 TiB growth limit.

That is correct.
Original install was done in one shot as 6x3TB.... (not incremental).

I started formatting 3TB's I took out and I will backup everything in NAS to these.
Then I've no idea.....best sounds like to reset to factory defaults with 6x4TB's in place...then copy everything back...ufffff.

After you are backed up, you could alternatively try the off-line expansion process. Nothing to lose after all, if you are prepared to restore from backup.

If you decide to go with the factory default, you might as well go with flexraid RAID6 - not much point to xraid2 if you are at the 16 TB ceiling.

I don't recall if you are under warranty or not - support.netgear.com is another option you could try.

frusnet wrote:

StephenB wrote: I believe the plan was to go from 6x3TB dual redundancy (12 TB volume) to 6x4TB dual redundancy (16 TB volume). Original info was that the 6x3TB was the starting point. If all that is correct, then OP hasn't hit either expansion limit. Of course if the original install was actually done in stages he might be hitting the 8 TiB growth limit. That is correct. Original install was done in one shot as 6x3TB.... (not incremental). I started formatting 3TB's I took out and I will backup everything in NAS to these. Then I've no idea.....best sounds like to reset to factory defaults with 6x4TB's in place...then copy everything back...ufffff.

it sounds like you started with 6x 3tb SINGLE redundancy.

I'm currently using X-RAID2 with dual-redundancy. I cut&paste volume: Volume C: Online, X-RAID2, 6 disks, 81% of 13 TB used

6x 3tb at dual redunancy would get you about 10-11tb not 13.

what does it say on the frontview > volumes page?

Wed May 7 09:04:35 EEST 2014 Data volume has been successfully expanded to 15740 GB.

this line here says you are already up to 16tb

meaning no matter what, your are not going to expand further without some kind of factory default.

TeknoJnky wrote:
it sounds like you started with 6x 3tb SINGLE redundancy. 6x 3tb at dual redunancy would get you about 10-11tb not 13. what does it say on the frontview > volumes page?

No, always had dual redundancy.
Still have 11TB.
Let me cut&paste volumes page:


Disk space 11 TB (73%) of 15 TB used
Configuration: RAID Level X-RAID2, 6 disks
Status: Redundant

RAID Disks:
Ch 1 : Seagate ST4000DM000-1F2168 [3726 GB] 3721 GB allocated
Ch 2 : Seagate ST4000DM000-1F2168 [3726 GB] 3721 GB allocated
Ch 3 : Seagate ST4000DM000-1F2168 [3726 GB] 3721 GB allocated
Ch 4 : Seagate ST4000DM000-1F2168 [3726 GB] 3721 GB allocated
Ch 5 : Seagate ST3000DM001-9YN166 [2794 GB] 2790 GB allocated
Ch 6 : Seagate ST3000DM001-9YN166 [2794 GB] 2790 GB allocated

and health page is:
Disk 1 Seagate ST4000DM000-1F2168 3726 GB , 36 C / 96 F , Write-cache ON OK
Disk 2 Seagate ST4000DM000-1F2168 3726 GB , 37 C / 98 F , Write-cache ON OK
Disk 3 Seagate ST4000DM000-1F2168 3726 GB , 35 C / 95 F , Write-cache ON OK
Disk 4 Seagate ST4000DM000-1F2168 3726 GB , 36 C / 96 F , Write-cache ON OK
Disk 5 Seagate ST3000DM001-9YN166 2794 GB , 41 C / 105 F , Write-cache ON OK
Disk 6 Seagate ST3000DM001-9YN166 2794 GB , 39 C / 102 F , Write-cache ON OK
Fan SYS 897 RPM OK
Fan CPU 1962 RPM OK
Temp SYS 51 C / 123 F [Normal 0-65 C / 32-149 F] OK
Temp CPU 25.5 C / 77 F [Normal 0-85 C / 32-185 F] OK
UPS 1 APC Back-UPS RS 550GI, Battery charge: 100%, 25 minutes OK

TeknoJnky wrote:
this line here says you are already up to 16tb meaning no matter what, your are not going to expand further without some kind of factory default.

That's exactly what I was afraid of :(

So most logical move would be to do a factory reset after backup's are finished.
Would it then see all 6x4TB without any issues or limitations?

Since these are "desktop" drives and they are very prune to malfunction, I really like to use that 2-disk-as-spare as in current setup.
Is there anything you would recommend besides X-Raid2 even after factory reset? (I was thinking using same X-Raid2 again)

TeknoJnky wrote:
it sounds like you started with 6x 3tb SINGLE redundancy. I'm currently using X-RAID2 with dual-redundancy. I cut&paste volume: Volume C: Online, X-RAID2, 6 disks, 81% of 13 TB used 6x 3tb at dual redundancy would get you about 10-11tb not 13.

6x3TB single redundancy is 15 TB, or 13.6 TiB. So it looks like frusnet (or frontview) was somehow mistaken on dual redundancy.

TeknoJnky wrote:
what does it say on the frontview > volumes page? Wed May 7 09:04:35 EEST 2014 Data volume has been successfully expanded to 15740 GB. this line here says you are already up to 16tb

Well, not quite. The limit is 16 TiB, not 16 TB, so the ceiling is 16384 GiB, not 15740. BTW, 16 TB is 14901 GiB, so he is already above that ceiling.

The 15740 GiB size is consistent with single redundancy though. The 3x4TB+3x3 TB expansion worked. Single redundancy would 17 TB volume size, or 15832 GiB (ignoring snapshots, OS partition space, and other overhead). 15740 GiB sounds close enough, with that overhead subtracted off.

TeknoJnky wrote:
...meaning no matter what, your are not going to expand further without some kind of factory default.

I agree on the bottom line. Expansion to 4x4TB+2x3TB adds another 1 TB to the volume size - or 931 GiB. 15740+931 = 16671, which is over the 16 TiB ceiling.

frusnet - if your goal was to increase your original volume size, then you want single redundancy, not dual. 6x4TB dual redundancy is less space than 6x3TB single redundancy.

So (a) you do need a reset, and (b) that means you need to restore your data from backup, and reconfigure the NAS.
You can save the configuration if you like, but keep in mind that when you rebuild the NAS you
1. Reinstall addons
2. THEN restore the config
3. Finally restore the data.

Since you will need to reset, you might as well use flexraid (raid-5)

I am not very experienced in these NAS / RAID configurations at all, but I think I had chosen dual redundancy.
When I set it up first, out of 6x3tb = 18TB space, I had about 12TB space left for my files.
2 disks's space was kind of reserved for keeping the NAS running in case of failure.

That 12TB "usable" space is what I intended to upgrade, and therefore I got 6x4TB's for that reason.

One side note... a conflicting log message with above...

A disk was removed from the ReadyNAS. One or more RAID volumes are currently unprotected, and an additional disk failure or removal may result in data loss. Please add a replacement disk as soon as possible.

Doesn't this conflict with dual redundancy?
Maybe the X-Raid2 option I chose was single redundancy?? (then how come I had 12tb usable space out of 18TB's?)


I agree making backups is always a good idea (especially now!), I am in process of making backups even as I wrote these.

After all these backups are finished, yes I can and will do what is right.

Let me summarize basically what I need, maybe it's easier to find a conclusion
- I need more space than 12TB... whole reason of getting 6x4TB disks. After devoting 2 disks to safety I expect to have 16TB usable space (at least).
- Since I'm using "desktop" level drives, I will need the NAS to be up and running even 2 drives fail at the same time. I can live with 1 drive failing too but I think it's too much of a risk.
- Which RAID level should be optimum based on above with 6x4TB disks?
these are my basic needs.

Optionally it would be nice to have answers to these below as well:
- In the future, ability to upgrade to 6x6TB maybe?
- In a nutshell pros/cons of OS6
- How to do off-line expansion process? Never heard that one before. Or shall I simply restore to factory defaults? (after all I only have 3 dirs to assign and 1 add-on anyway...no biggie, can redo all settings in matter of minutes)
- "If you decide to go with the factory default, you might as well go with flexraid RAID6 - not much point to xraid2 if you are at the 16 TB ceiling. "
This 16TB ceiling is for x-RAID2? Basically which Raid configuration you think would best serve above criteria.

Guys, again, tyvm for all replies really.

frusnet wrote:

I am not very experienced in these NAS / RAID configurations at all, but I think I had chosen dual redundancy. When I set it up first, out of 6x3tb = 18TB space, I had about 12TB space left for my files. 2 disks's space was kind of reserved for keeping the NAS running in case of failure. That 12TB "usable" space is what I intended to upgrade, and therefore I got 6x4TB's for that reason. One side note... a conflicting log message with above... A disk was removed from the ReadyNAS. One or more RAID volumes are currently unprotected, and an additional disk failure or removal may result in data loss. Please add a replacement disk as soon as possible. Doesn't this conflict with dual redundancy? Maybe the X-Raid2 option I chose was single redundancy?? (then how come I had 12tb usable space out of 18TB's?)

The message you ask about applies to single redundancy. You removed one disk, and the volume is intact but not protected. That's single redundancy. If you had dual, then the volume would still be protected.

Single redundancy is the xraid2 default. You would have needed to explicitly set it up for dual redundancy back when you initially set it up. It's pretty clear at this point that (a) either you didn't do that at all, or (b) you tried to do it, but somehow ended up with single redundancy anyway.

One complication on total space is that there are two sets of units floating around. For historical reasons, drive manufacturers use multiples of 10 (1000 bytes = 1 KB, 1000 000 bytes = 1 MB). Windows and many other OS use multiples of 1024 (1024 bytes = 1 KB, 1024*1024 bytes = 1 MB, etc). These "power-of-two" units are technically called KiB, MiB, GiB, TiB, but Netgear (and Windows) leave out the middle "i'. This didn't matter much when 20 MB was a large disk, but as capacities grow the differences between the units becomes substantial.

6x3TB gives you 15 TB (using power of ten), but only 13.6 TiB (using 1024 multiples). The NAS should have reported 13, not 12 - but you might not have noticed the free space until after you had already copied some stuff.

frusnet wrote:

Let me summarize basically what I need, maybe it's easier to find a conclusion - I need more space than 12TB... whole reason of getting 6x4TB disks. After devoting 2 disks to safety I expect to have 16TB usable space (at least). - Since I'm using "desktop" level drives, I will need the NAS to be up and running even 2 drives fail at the same time. I can live with 1 drive failing too but I think it's too much of a risk. - Which RAID level should be optimum based on above with 6x4TB disks?

Two main points.

One is the TiB/TB thing again. 6x3TB single redundancy is 15 TB (13.6 TiB). 6x4TB dual redundancy is 16 TB (14.5 TiB). By going to dual redundancy, you are getting extra protection, but only 1 TB of extra space.

Dual redundancy is better than single. But backups are what are really needed in either case. RAID gives you two benefits, and they are in the convenience category not so much vital protection. The first is that if you have a routine disk failure, you can pop in a new one - keeping your data available, and not going through the bother of a restore from backup. The second is that you can expand the volume (without destroying it, creating a larger one, and then restoring the data). In your case, since you've hit the expansion ceiling, so you only get the first benefit.

Some people (including some posting on your thread) think dual-redundancy is the way to go with larger disks. Personally I think single redundancy is fine, as long as you have backups. I haven't seen any evidence that larger disks fail more frequently than smaller ones. But it is obviously true that it is more painful to restore a bigger volume when it does fail. So there is no right answer here. RAID-6 (same as "dual redundancy xraid2") offers more protection from drive failures, at a cost of losing more capacity. For some people, that's a price they are willing to pay. For others, it isn't.

frusnet wrote:
- In the future, ability to upgrade to 6x6TB maybe?

I believe you can do this with flexraid, by creating a second 6x2TB volume to use the extra space. Though I haven't tried to do that myself. OS6 xraid2 would just expand, as it doesn't have the 16 TiB ceiling (because it uses the btrfs file system).

frusnet wrote:
- In a nutshell pros/cons of OS6

It's newer, and has some better features (more useful snapshots and antivirus protection are probably most important to you). It has no expansion limits.

The bad news is that Netgear support won't help you if you have issues, since Netgear hasn't released OS6 for the Ultra-6. The hardware warranty still applies of course. The in-between news is that OS6 is still a bit of a work-in-progress. Though the recent releases have resolved most of the growing pains.

If you want to move into OS6, then now would be a good time to do it - since you need to rebuild the NAS from scratch anyway. You can reverse the process, but that also requires rebuilding the NAS from scratch. There's a quite long thread on OS6 for legacy devices, you should browse through it if you are interested.

frusnet wrote:
- How to do off-line expansion process?

Given the discovery that you actually only have single redundancy, this process won't work for you anyway. So don't worry about it.

frusnet wrote:
- "If you decide to go with the factory default, you might as well go with flexraid RAID6 - not much point to xraid2 if you are at the 16 TB ceiling. " This 16TB ceiling is for x-RAID2? Basically which Raid configuration you think would best serve above criteria.

The 16 TiB ceiling is for an ext4 volume with 32 bit inode addressing. The NAS sets up the file system to use 32 bit addressing by default, unless the original raid volume size is > 16 TiB. Once done, there is no safe way to expand the inodes to 64 bits. That 32-bit decision made sense when it was made (back when 2 TB disks were the biggest you could buy), and it still works out well for the 4-bay units. But with 4 TB and larger drives available today, it isn't the best.

It'd be nice if Netgear made a fairly small mod to always create a 64 bit inode volume. There are several use cases where that would be helpful to the installed base of x86 users.

frusnet wrote:
TeknoJnky wrote: it sounds like you started with 6x 3tb SINGLE redundancy. 6x 3tb at dual redunancy would get you about 10-11tb not 13. what does it say on the frontview > volumes page? No, always had dual redundancy. Still have 11TB. Let me cut&paste volumes page: Disk space 11 TB (73%) of 15 TB used Configuration: RAID Level X-RAID2, 6 disks Status: Redundant

That is single redundancy.

it would say (dual redundancy) or something to that effect, i can't remember the exact wording at the moment.