NETGEAR is aware of a growing number of phone and online scams. To learn how to stay safe click here.
Forum Discussion
NetWhiz
May 27, 2025Guide
ReadyNAS Pro 6 - Stuck on booting while checking fs
I have searched for similar errrors on here, but none seem to either work or be related as to my situation.
My Pro 6 just started to freeze a couple days ago while it was running. I had updated it to OS6 a long while ago. Thinking it might just be a random error, I restarted the device and now it gets to the checking root fs and stops around half way (sometimes more or less). I have tried the following:
- OS Reinstall - Completes and boots to same percentage.
- Disk Tests ran fine and rebooted itself (though now this is no longer an option in the boot menu)
- USB Recovery ran and shutdown. Boots back to same percentage.
- Tech Support mode works
- Tried start_raids and it seemed to see every drive.
- Ran some mdadm commands to examine the drives and array as found in other posts on here with no glaring errors found.
- Running a 'smartctl -t long /dev/sda' now.
Not sure what else to do to get it to boot so I can get my files (prefer it to continue being useful but can get soem other NAS and move my data as long as I can get to it).
Thoughts/ideas/help?
Thank you.
27 Replies
- StephenBGuru - Experienced User
NetWhiz wrote:
My Pro 6 just started to freeze a couple days ago while it was running. I had updated it to OS6 a long while ago. Thinking it might just be a random error, I restarted the device and now it gets to the checking root fs and stops around half way (sometimes more or less). I have tried the following:
Did you upgrade the RAM, or is it still using the default 1 GB?
Did you try using the boot option that skips the FS check?
How full is the OS partition?
- NetWhizGuide
NO, still using the default RAM.
Yes, I did try the FS Skip but it still hangs during the Root FS check stage.
Running the following:
# mount --bind / /mnt # du -d1 -h /mnt 4.0K /mnt/tmp 0 /mnt/sysroot 0 /mnt/sys 8.0K /mnt/run 0 /mnt/proc 0 /mnt/opt 0 /mnt/mnt 0 /mnt/media 0 /mnt/home 52.0K /mnt/var 9.5M /mnt/usr 396.0K /mnt/sbin 2.6M /mnt/lib 2.4M /mnt/etc 420.0K /mnt/bin 16.0K /mnt/root 0 /mnt/dev 15.5M /mnt
- StephenBGuru - Experienced User
NetWhiz wrote:
NO, still using the default RAM.
Some have found that isn't enough, so I now recommend upgrading to between 2 GB and 4GB. That is still inexpensive. 8 GB is possible, but expensive and it is hard to find 4 GB memory sticks that are compatible.
NetWhiz wrote:
15.5M /mnt
Looks like you are running the boot OS and not the OS partition (that is, you ran start_raids instead of rnutil chroot). The OS is much larger than 15.5M.
You could try mount /dev/md0 /mnt
if that works you could try checking it from ssh.
- StephenBGuru - Experienced User
NetWhiz wrote:
root@2H0523RC00354:/# btrfs check /
ERROR: not a regular file or block device: /Ok. Try btrfs check /sysroot (or even btrfs /dev/md0 )
NetWhiz wrote:
lsblk
Ok. It looks like there is no volume expansion. But sdb3 (disk 2) does not appear to be in the md127 RAID array (e.g., the data volume).
Can you also post the output of cat /proc/mdstat ?
Did smartctl finish with sda? If it did, what were the results? It would be good to run smartctl on sdb as well.
- NetWhizGuide
root@2H0523RC00354:/# btrfs check --force /dev/md0 WARNING: filesystem mounted, continuing because of --force Checking filesystem on /dev/md0 UUID: 6adf6613-a823-4a15-bdd5-fccd87d87ab7 checking extents checking free space cache checking fs roots checking csums checking root refs found 1371430912 bytes used, no error found total csum bytes: 1256992 total tree bytes: 13959168 total fs tree bytes: 11517952 total extent tree bytes: 835584 btree space waste bytes: 2825441 file data blocks allocated: 1847738368 referenced 1334403072
root@2H0523RC00354:/# cat /proc/mdstat Personalities : [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] md127 : active raid5 sda3[0] sdf3[5] sde3[6] sdd3[3] sdc3[2] 14627079040 blocks super 1.2 level 5, 64k chunk, algorithm 2 [6/5] [U_UUUU] md0 : active raid1 sda1[0] sdf1[10] sde1[9] sdd1[8] sdc1[7] sdb1[6] 4190208 blocks super 1.2 [6/6] [UUUUUU] md1 : active raid1 sda2[0] sdb2[1] 523712 blocks super 1.2 [2/2] [UU] unused devices: <none>
smartctl --test short /dev/sdb
SMART Self-test log structure revision number 1 Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error # 1 Short offline Completed without error 00% 29901 - # 2 Short offline Completed without error 00% 29898 - # 3 Extended offline Completed without error 00% 29876 -
- NetWhizGuide
Should I do the following:
mdadm --manage /dev/md127 --add /dev/sdb3
to add the disk to the array?
- StephenBGuru - Experienced User
NetWhiz wrote:
Should I do the following:
mdadm --manage /dev/md127 --add /dev/sdb3
to add the disk to the array?I wouldn't do that. The array is assembled, and I don't think the issue with sdb3 is interfering with your boot. It also doesn't seem to be an issue with the root.
I think the next step is to do a btrfs check /dev/md127
- StephenBGuru - Experienced User
NetWhiz wrote:
# btrfs check /dev/md127
These errors are the real problem.
See if the file system can be mounted read-only with mount -o ro /dev/md127 /data That should be safe to try.
If the volume can be mounted, then the best approach is to backup all the data, do a factory default, and then restore the data from your backup.
- NetWhizGuide
It does mount. However, how do i get it off to another drive since I can only boot into Tech Support mode? I have an enclosure with 13.5 TB free but it is eSATA only.
Is there a way to get the unit to boot w/o trying to do anything with the /dev/md127 volume so I can then mount it in readonly and copy the data off across teh network?
- NetWhizGuide
The root fs check is where it is hanging. Can you (or someone rebuild that partition like mdgm / mdgm-ntgr) so it boots back up? I can then grab the data off it and then reset the NAS to factory and recreate the volume again (obviously).
Related Content
NETGEAR Academy

Boost your skills with the Netgear Academy - Get trained, certified and stay ahead with the latest Netgear technology!
Join Us!