Volume scan failure (corrupt snapshot?) after 4.2.20 upgrade

[grahamblandford]

Hi ladies and gents,

I upgraded my firmware to 4.2.20 last week and have subsequently been unable to perform a volume scan/error-free consistency check.

I don't appear to have any data issues with my volume, all green lights, etc. But the error I get when trying the scan seems to refer to a snapshot...

This is the volume scan error:

***** File system check performed at Tue Jun 5 12:11:44 EDT 2012 *****
fsck 1.41.14 (22-Dec-2010)
/dev/c/c: clean, 23699/152168448 files, 1893203768/2434678784 blocks
fsck.ext4: Attempt to read block from filesystem resulted in short read while trying to open /dev/c/c_2012_05_28_02_00
Could this be a zero-length partition?

I believe others _may_ have experienced this and there might be a fix - to remove the snapsht manually - but can't find a definite link. I have a basic understanding of unix-based OS, so I can follow instructions reasonably well.

Any ideas guys?

I have a ReadyNAS Ultra 6 (volume is 6x2TB X-Raid2 configuration (9250Gb) )

Thanks in advance.
Graham

[de_niro]

Ultra series do not have snapshot function,please contact support center to help you delete current defective snapshot and retrieve extra space that snapshot released.

[grahamblandford]

Thanks. I hadn't even considered using tech. support...

Graham

[sarcasm]

I am also seeing this error on an Ultra 4 starting today.

My /dev/c/ directory contains:

lrwxrwxrwx 1 root root 15 2012-10-22 00:18 c -> /dev/mapper/c-c
lrwxrwxrwx 1 root root 32 2012-10-22 00:18 c_2012_10_07_03_00 -> /dev/mapper/c-c_2012_10_07_03_00

and the error is:

fsck.ext4: Attempt to read block from filesystem resulted in short read while trying to open /dev/c/c_2012_10_07_03_00
Could this be a zero-length partition?

I can contact support of course but it seems like this problem is common enough that there should be public documentation of how to resolve it.

Also, on the date of the snapshot (October 7) my NAS locked up and I had to power it off hard. When it came back up, everything seemed fine except I had lost all of the files that I had created in the past 12 hours. It wasn't a huge deal for me but I had no clue why a system freeze would cause that. I subsequently ran a full fsck and it found no problems.