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RN104 - Sudden loss of volume. V6.9.3. No Volumes Exist. Remove Inactive Volumes.
Hi All,
Running V6.9.3 on an RN104, 4 x WD Red 4TB drives installed, showing no errors, and suddenly on Tuesday evening lost the ability to write to any share. Unit has been running perfectly for weeks, so gave the system a reboot from the GUI.
On waking it came up showing that No Volume Exists, and under System, Volumes the following;
Running 'btrfs check --readonly /dev/md127' returns;
bytenr mismatch, want=17615033696256, have=17489338793984 ERROR: cannot read chunk root ERROR: cannot open file system
Looking in dmesg.log and filtering md125 returns;
[Tue Jul 3 19:31:48 2018] md: md125 stopped. [Tue Jul 3 19:31:48 2018] md/raid:md125: device sdd5 operational as raid disk 0 [Tue Jul 3 19:31:48 2018] md/raid:md125: device sda5 operational as raid disk 2 [Tue Jul 3 19:31:48 2018] md/raid:md125: device sdc5 operational as raid disk 1 [Tue Jul 3 19:31:48 2018] md/raid:md125: allocated 3246kB [Tue Jul 3 19:31:48 2018] md/raid:md125: raid level 5 active with 3 out of 3 devices, algorithm 2 [Tue Jul 3 19:31:48 2018] md125: detected capacity change from 0 to 2000119660544 [Tue Jul 3 19:31:49 2018] BTRFS: device label 2fe5bdee:data devid 3 transid 202027 /dev/md125 [Tue Jul 3 19:31:50 2018] BTRFS critical (device md125): unable to find logical 22847651840 len 4096 [Tue Jul 3 19:31:50 2018] BTRFS critical (device md125): unable to find logical 22847651840 len 4096 [Tue Jul 3 19:31:50 2018] BTRFS critical (device md125): unable to find logical 22847651840 len 4096 [Tue Jul 3 19:31:50 2018] BTRFS critical (device md125): unable to find logical 22847651840 len 4096 [Tue Jul 3 19:31:50 2018] BTRFS critical (device md125): unable to find logical 22847651840 len 4096 [Tue Jul 3 19:31:50 2018] BTRFS critical (device md125): unable to find logical 22847651840 len 4096 [Tue Jul 3 19:31:50 2018] BTRFS error (device md125): failed to read chunk root [Tue Jul 3 19:31:50 2018] BTRFS error (device md125): open_ctree failed
Filtering md126, returns;
[Tue Jul 3 19:31:48 2018] md: md126 stopped. [Tue Jul 3 19:31:48 2018] md/raid:md126: device sdb4 operational as raid disk 0 [Tue Jul 3 19:31:48 2018] md/raid:md126: device sdc4 operational as raid disk 3 [Tue Jul 3 19:31:48 2018] md/raid:md126: device sdd4 operational as raid disk 2 [Tue Jul 3 19:31:48 2018] md/raid:md126: device sda4 operational as raid disk 1 [Tue Jul 3 19:31:48 2018] md/raid:md126: allocated 4294kB [Tue Jul 3 19:31:48 2018] md/raid:md126: raid level 5 active with 4 out of 4 devices, algorithm 2 [Tue Jul 3 19:31:48 2018] md126: detected capacity change from 0 to 3000185585664 [Tue Jul 3 19:31:48 2018] BTRFS: device label 2fe5bdee:data devid 2 transid 202027 /dev/md126
Filtering md127;
[Tue Jul 3 19:31:46 2018] md: md127 stopped. [Tue Jul 3 19:31:47 2018] md/raid:md127: device sda3 operational as raid disk 0 [Tue Jul 3 19:31:47 2018] md/raid:md127: device sdd3 operational as raid disk 3 [Tue Jul 3 19:31:47 2018] md/raid:md127: device sdc3 operational as raid disk 2 [Tue Jul 3 19:31:47 2018] md/raid:md127: device sdb3 operational as raid disk 1 [Tue Jul 3 19:31:47 2018] md/raid:md127: allocated 4294kB [Tue Jul 3 19:31:47 2018] md/raid:md127: raid level 5 active with 4 out of 4 devices, algorithm 2 [Tue Jul 3 19:31:47 2018] md127: detected capacity change from 0 to 5986292072448 [Tue Jul 3 19:31:48 2018] BTRFS: device label 2fe5bdee:data devid 1 transid 202027 /dev/md127
Any help gratefully received, as backup is not up to date (yes I know, be kind đ)
Many thanks!
Nick
4 Replies
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Thanks for the logs. You've got a triple-layer RAID array with a problem on the md125 layer.
It looks like your disks are healthy.Have you tried booting into volume read-only mode?
If your data still isn't accessible I'd suggest contacting support. There are costs involved with a data recovery attempt which may ultimately prove to be unsuccessful.Hi MDGM,
Thanks for the response. I had tried to boot it as a Read-Only volume and still no shares or volume.
I am very well versed in RAID arrays, as I am Technical Director of a Post-Production house, but not an expert on BTRFS. Could you briefly explain why the ReadyNAS has 3 layers? I look after huge Stornext and Windows arrays on a daily basis, and this is a new one to me, and why would this cause such a failure of the Filesystem?
I will contact support, but it would be great to get your non-Netgear view ;-)
Many thanks,
Nick
If you look at smart_history.log you'll see that your system has had disks with 3 different capacities. So it's had to add additional RAID layers for the vertical expansion. That's why you have a md125, md126 and md127, not just a md127.
Whilst having multiple RAID layers is not a problem it can make investigation a little more involved e.g. if the RAID won't start (which isn't the case here).
There are free tools for Linux that can be used to attempt to recover data from a BTRFS filesystem.There is also paid software for Windows.
Situations like this are considered on a case by case basis. When it comes to data recovery attempts it's important to proceed carefully to maximise the chances of success.
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