× NETGEAR will be terminating ReadyCLOUD service by July 1st, 2023. For more details click here.
Orbi WiFi 7 RBE973
Reply

I have 2 volume groups showing, after adding a disk- is something wrong?

IanWilson
Aspirant

I have 2 volume groups showing, after adding a disk- is something wrong?

Sorry - this will be a long post to explain what I am seeing. I want to know what I should do about this situation to best protect my data.

 

I have an RN426, and I had 2x 4TB and 2x 6TB drives configured as XRAID2. I had a single data volume which has 6.37TB of data and 2.62TB of snapshots on it. I have backups of some data, other data (about 4TB) is not backed up as yet. All had been stable and no issues for over 2 years.

 

I bought and added a 1x 8TB drive into the array (the plan being to upgrade to 6x 8TB drives slowly using XRAID2). However after doing so, once the drive had been accepted and the volume expanded, I noticed something rather odd.

 

It appears that the unit has dropped out of XRAID2 into Flex-RAID, and I now have 2x volume groups.  I still see a single /data volume and can access ALL my data without any issues, and the unit appears stable. I have sat on this for a month, wondering if it would revert, there has even been a firmware upgrade recently but that didn't help.

 

The latest firmware is on board and the drives are all IronWolf Seagate Drives.

 

So I see 1x volume group  which shows all 5x drives in it, and lists them as 5900rpm, which is not true of the 8TB drive. I can then see a second volume group which has the 2x 6TB and 1x 8TB drives in it, listed as 7200rpm drives.

 

Does anyone know what I should do to get back to XRAID2?  I have a further 8TB drive I want to add into the array, but with it currently being in FlexRAID I don't know whether to add it or not just now.

 

Is this a bug, a sign of impending doom, and what should I do about it?Screenshot 2021-01-20 at 12.58.45.pngScreenshot 2021-01-20 at 12.58.36.png

 

 

Model: RN426|ReadyNAS 426 – High-performance Business Data Storage - 6-Bays
Message 1 of 7
IanWilson
Aspirant

Re: I have 2 volume groups showing, after adding a disk- is something wrong?

Sorry tried to add screenshot photos but all I see is a triangle ! I'll add them as files ...

Message 2 of 7
IanWilson
Aspirant

Re: I have 2 volume groups showing, after adding a disk- is something wrong?

and the 2nd...

Message 3 of 7
StephenB
Guru

Re: I have 2 volume groups showing, after adding a disk- is something wrong?

All embedded images need to be reviewed and approved by a mod before they are shown.  I also can approve them (and just approved yours).  

 


@IanWilson wrote:

 

It appears that the unit has dropped out of XRAID2 into Flex-RAID, and I now have 2x volume groups.  

FWIW, Netgear just calls it XRAID now.  There are actually three variants (the original in 4.1.x NAS, the second generation in 4.2.x and 5.3.x NAS, and the current version in OS-6).  Netgear called the second generation XRAID2, but gave up on that when they introduced the OS-6 NAS.

 

Let's start with the two RAID groups.  That is completely normal (and you'd have two RAID groups in XRAID also, though the system wouldn't show you that).  That's how the NAS handles unequal size disks.

 

There is a 4 TB partition on each disk, and those are used in a 5x4TB RAID-5 group.  There's a second 2 TB partition on the 6 TB disks (and now the 8 TB drive), which is used in a 3x2TB RAID-5 group.  These are concatenated into a single volume.

 

When you are done with your disk upgrade, you'll end up with three RAID groups - 6x4TB + 6x2TB + 6x2TB.

 


@IanWilson wrote:

Is this a bug, a sign of impending doom, and what should I do about it?


No sign of impending doom.

 

The first thing to try is to click on the XRAID control on the right of the volume tab.  See if that will put you back into XRAID - showing a green stripe through the control.  If that works, you are good to go.

 

If not, then you have three options:

  1. Stay with FlexRAID. You'll need to do a bit more work as you upgrade - for instance, you'll need to create the third RAID group after you add the next 8 TB drive, and add that to your existing volume via the web UI.  You might want to review the manual (starting on page 39) here: https://www.downloads.netgear.com/files/GDC/READYNAS-100/READYNAS_OS_6_SM_EN.pdf
  2. You can do a factory default, and rebuild the NAS from scratch - reconfiguring it, and restoring data from backup.
  3. You can see if paid Netgear support can help force your system back into XRAID w/o needing the default.
Message 4 of 7
IanWilson
Aspirant

Re: I have 2 volume groups showing, after adding a disk- is something wrong?

Thanks for your input @StephenB 

My first plan is to take a full backup of all data next before any other action.

I am reluctant to rebuild from scratch if I can avoid this at all.

 

I have tried pressing the XRAID button but I get an error : "You are attempting to switch from Flex-RAID to X-RAID. This is not possible because you have expanded volumes."

 

If I end up with 3 FlexRAID groups, (2x 4TB, 2x 6TB, and 2x 8TB) is there the possibility I may be able to then force it back into XRAID myself with the XRAID panel button?

 

is my /data volume now spread across the two volume groups or just on one of the volume groups?  I'm confused?

 

If I remove my 2x 4TB drives, leaving the 2x 6TB and 1x 8TB (in otherwords keep Group 2 in the NAS physically) could my /data volume remain intact?  If so, could I then try forcing back into XRAID, and adding the new 1x 8TB disc to that set?

 

Any idea how much support charges?

 

 

Message 5 of 7
StephenB
Guru

Re: I have 2 volume groups showing, after adding a disk- is something wrong?


@IanWilson wrote:

I have tried pressing the XRAID button but I get an error : "You are attempting to switch from Flex-RAID to X-RAID. This is not possible because you have expanded volumes."


I was afraid you might see that.  Whatever pushed you into Flex-RAID must have happened either before you inserted the 8 TB drive, or during the expansion.

 


@IanWilson wrote:

 

is my /data volume now spread across the two volume groups or just on one of the volume groups?  I'm confused?

 


First of all, they are called RAID groups - not volume groups.

 

I tried to explain this before, but apparently it was too confusing for you.  Maybe think of this as a wedding cake.  The bottom tier is 5x4TB RAID-5  at the moment, and the second tier on top is 3x2TB RAID-5.  When you add another 8 TB disk, the bottom tier would be 6x4TB RAID-5, and the second tier would be 4x2TB RAID-5.  With X-RAID, the system would automatically create a third tier in the "cake" of 2x2TB RAID-1.  And when you upgraded an existing disk to 8 TB, it would convert that third tier to 3x2TB RAID-5.

 

All of these cake "tiers" are concatenated into a single BTRFS volume.

 

As I also tried to say before, your data was spread over these two RAID groups before the system switched into FlexRAID. Your original 2x4TB+2x6TB volume also had two RAID groups what were concatenated together - a 4x4TB RAID-5 "bottom tier" combined with a 2x2TB RAID-1 "second tier".

 

All X-RAID does is automate the RAID group management - so you don't need to think about it.  Flex-RAID gives you full control over it (and it does let you choose RAID modes that X-RAID doesn't use).  So you can certainly follow through on your plan with Flex-RAID, you just need to read up on it a bit more, and of course follow up here if you don't fully understand what you are doing.

 

Still, it is a bit of a mystery on why the system jumped out of X-RAID mode in the first place.

 


@IanWilson wrote:

 

If I remove my 2x 4TB drives, leaving the 2x 6TB and 1x 8TB (in otherwords keep Group 2 in the NAS physically) could my /data volume remain intact?  

 


No. Removing two drives from your array will result in immediate loss of all your data.  Removing one disk will give you a degraded volume - making your data more vulnerable.  Don't try manipulating your disks, it won't help and almost certainly will hurt.

 


@IanWilson wrote:

 

If I end up with 3 FlexRAID groups, (2x 4TB, 2x 6TB, and 2x 8TB) is there the possibility I may be able to then force it back into XRAID myself with the XRAID panel button?

 


No.  BTW, you couldn't end up with that set of RAID groups unless you destroy the volume and start over. Hopefully the explanation above makes that clear to you.  You'd have a 6x4TB RAID-5 group (all 6 disks), a 4x2TB RAID-5 group (6 and 8 TB disks) and a 2x2TB RAID-1 group (8 TB disks). 

 


@IanWilson wrote:

 

My first plan is to take a full backup of all data next before any other action.


Always a good plan.  FWIW, Netgear always recommends having a full backup before you add or replace disks.  My own advice is to always have a full backup no matter what, as RAID is not enough to keep your data safe.

 


@IanWilson wrote:

Any idea how much support charges?

 


I haven't looked lately, and I think it does vary by geography.  Last time I heard, per-incident support was in the $75-$100 range.  Not sure if per-incident would cover this, and per-incident can be hard to find at my.netgear.com - you might want to reach out via private message to one of the mods ( @JohnCM_S or @Marc_V ) and see if they can facilitate.  You send a PM using the envelope icon in the upper right of the forum page.

Message 6 of 7
IanWilson
Aspirant

Re: I have 2 volume groups showing, after adding a disk- is something wrong?

Thanks @StephenB  - that all makes a bit more sense to me.

 

So superficially, there is no going back to XRAID easily, unless support go "fiddling" via SSH - and that carries the risk of complete data loss potentially and a headache carrying out a long restore !

 

Hmm, at least I have time to think more about this while setting up a backup.  Thats the one issue with the hugh capacity NASs I guess, the more data you have, the longer and more complex the backup.

Message 7 of 7
Top Contributors
Discussion stats
  • 6 replies
  • 1025 views
  • 1 kudo
  • 2 in conversation
Announcements