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ReadyNAS NV+ data recovery one bad disk

nwwoods
Aspirant

ReadyNAS NV+ data recovery one bad disk

ReadyNAS NV+ v1, frontview 4.1.16, 4 1TB Samsung spinpoint drives, X-RAID (3 data drives, 1 parity AFAIK)

 

It all started with noticing vast swaths of files/directories seemed to no longer be present.  Tried to reboot and got the "Found bad disk" error/hang.   Tried the Skip Disk Check POST option but it still stopped with Found Bad Disk.  Eventually I got to the log which said "A SATA reset has been performed on one or more of your disks that may have affected the RAID parity integrity..." 

 

By backing out drives one at a time, discovered disk 2 was the source of the error.  Anaylzed it with HDDSCAN from a PC and saw it had excess sector reallocations.  Bought a new hard drive, put it in and booted, it came up but refused connections to frontview.  Analyzed the other 3 disks and all are clean SMART status.  Only disk 2 had issues (sector reallocations).

 

More experimenting, discovered only if I also removed disk 1 would it boot and be accessible via Frontview.  But of course with only 2 disks, no data, and irrecoverable.  

 

Installed ext2explore and I can browse each of the 4 disks from a PC, including disk 2.  Disks 1,2,3 have a collection of partitions that seems to include a complete Linux OS on each.  Disk 4 seems to be unpartitioned, but I assume it is parity somehow.

 

I see files in the root folder of each of the disks that is the name of each of the shares.  But they're not folders, and I don't see the contents of the shares.  Where should the shares contents be?  How can I get at my data?  If it's a stripe set I guess I need to mount all of them simultaneously and use some other tool to read them?

 

 

Model: ReadyNAS RND4000|ReadyNAS NV+ Chassis only
Message 1 of 6
StephenB
Guru

Re: ReadyNAS NV+ data recovery one bad disk

When you booted with disk 1 inserted, did you look at the status with RAIDar?

 

Maybe power down, insert it again, and try booting using the "skip volume check" option.

 

The RAID array can be mounted in an x86 linux system: http://home.bott.ca/webserver/?p=306

Message 2 of 6
nwwoods
Aspirant

Re: ReadyNAS NV+ data recovery one bad disk

Thanks for responding.

 

With disk 1 inserted, RAIDar showed the disk healthy, but I got connection refused from Frontview or browsing.  The only way I could rouse Frontview was with only disks 3,4 inserted.

 

I was able to boot with 3,4 and add 1,2 and Frontview showed them, but resync was grayed.  I used the debugger to enable it and start a resync, but the resync failed.  Not surprising.

 

I did go farther back in the logs and noted an alert about disk 1 from way back in April.  Combined with the recent fail on disk 2, 2 failed disks from ReadyNAS' point of view, so no wonder. 

 

The drives are all readable as I mentioned before, with ext2-explorer.  I bought R-Studio and can read each of the drives with it also.  I bought a pair of 2TB drives and did a factory reset so I basically have a fresh ReadyNAS.  Am working through the original disks one by one on a PC with R-Studio and recovering.  backup share from Disk 1 in progress now.  It says 8 days to finish.  Recovered contents so far are good.  Guess I could have gone the Ubuntu route per http://home.bott.ca/webserver/?p=306 and saved 80 bucks bu R-Studio looks real nice and reminds me of Norton Utilities from the old days.

 

At least the drives seem to be independent so I can recover them one at a time.  I thought X-RAID with 4 disks was RAID-5 like, but so far I don't see any striping, thankfully.  It's just going to take a long time.

 

Message 3 of 6
StephenB
Guru

Re: ReadyNAS NV+ data recovery one bad disk

There is striping with XRAID (which on an NV+ is using RAID4 - dedicated parity disk)

Message 4 of 6
nwwoods
Aspirant

Re: ReadyNAS NV+ data recovery one bad disk

Thank you @StephenB.  Fascinating.

 

How does the block level striping work at the file level?  Assuming 1MB blocks for SAMBA, I would expect a 3MB file to be split across 3 disks in a 4-disk system.  But what I am seeing is mp3's and jpegs in that size range are fully on the one disk.  Just restored a 3GB mpeg also from the same disk. 

 

Message 5 of 6
StephenB
Guru

Re: ReadyNAS NV+ data recovery one bad disk


@nwwoods wrote:

 How does the block level striping work at the file level?  

 


RAID always works below the file system level (creating a virtual disk partition of block storage).  

 

I believe the stripe size for your NAS is 32K.  So I am confused on how you are recovering using just one disk.

Message 6 of 6
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