I have a ReadyNAS NV+ with 4x2TB Seagate Barracuda.
Disk3 went bad.
The unit was ‘booting up’ forever and the reset button was pressed in order to try to have it boot-up properly but it didn’t.
Then I replaced the damage disk3 with a brand new one (exact same)
It did say the unit was re-syncing and the led on disk3 was flashing.
After a very long time Raidar show green checked marks on all drives. However, on the unit itself disk3 green light kept on flashing like if sync was still going on.
I could access the admin page from Raidar button but the home page says “Volume C offline”
I was reading that the unit should be able to work with only 3 drives, I shutdown the unit and remove disk3. Bootup again and same scenario: I could access the admin page but still says “Volume C offline”.
After calling NETGEAR support and sending my logs, they told me that it appears that the X-RAID array was corrupted but it was most likely recoverable.
I am planning to pay the $75 to go with the next support level and have them fix it for me, but I thought it would be very helpful for the community to understand more in detail how they are going to do it.
My plan is to ask first to make the system booting properly with only the 3 good drives, but could they realistically rebuild the array with only 3 disks if they can recover a ‘kind of’ proper backup of the array configuration (or superblock I am not sure) that was created when the 4 disks were all working properly.
I have installed the openSSH add-on and I’d like to see where would be those precious proper configuration files.
Also, I thought someone could explain us in detail what to do with them and how to rebuild the X-RAID array from them.
Of course, I am trying to recover the data on my ReadyNAS and not try to reformat and start all over from scratch....
There are two aspects here, one is recovery of the physical sectors on the bad disk, and the other is repairing the file system.
If the remaining 3 disks are intact, then everything that was on the disk 3 can be recovered from the rest - that is what RAID-5 does. If there are some bad blocks found on the three disks, then there would be some additional corruption (on top of what ever is already there).
If there is file system damage (perhaps due to pulling the plug or something similar), then that also needs to be addressed (that's where your superblock stuff comes in).
Data recovery could easily cost more than the $75 per incident support (entry fee would be $200 after that I think). But it is quite possible that they can remount your array with the three good drives w/o needing data recovery. If they can do that, your first step should be to make a backup (before replacing the fourth disk).
Overall, if you are using paid support it is best to give Netgear the steering wheel on the process steps.
Thank you for the valuable tips, but I think I need to explain a bit further the purpose of my post here. I don't Realy need to recover the data on my NAS because I had it backup.
However I am very interested to learn how to do it and it's only for educational purpose. If I had valuable data I wouldn't even try to do it myself since $75 + $200 are highly fair and reasonable price and I would recommend anybody to go for it and don't take a chance.
In my case, as you pointed perfectly right, I did unplugged the unit probably more than once and I am sure that now the filesystem is indeed damaged/corrupted.
So, my questions are:
1) How do you go from there?...
2) How do you identify if it is recoverable or not?...
3) Is X-RAID EXACTLY the same as RAID5?...
4) Should I try to rebuild the filesystem with a brand new disk in slot 3 or should try do it first with only the good 3 disks (knowing that the filesystem is damaged on them and the unit will not mount the Volume C) ?...
XRAID on the NV+ is RAID5. Later on they added vertical expansion, and that is more complicated. However, it still uses standard linux tools underneath.
I am thinking that attempting to replace disk 3 right now won't help (and could make things worse). Though since this is just a learning experience, you could certainly try it at some point.
First, remove the disk3 and boot the unit with only the 3 good disks
Yes. This often works.
Should I open a terminal in Ubuntu and mount the NAS there or should I SSH directly the ReadyNAS ?
If SSH is functioning on the NAS you could try mounting there. I don't know the exact steps though (and the info in the links might need some modification if you are executing it on the NAS). Perhaps PM mdgm?
The info in the link is assuming the disks are attached to the Ubuntu system.
Should I try to recreate the array first or check and repair the filesystem?...
I wouldn't try repairing the array until you sort out the file system issue.
