Just for my clarification regarding the role of parity and the parity check:

 

1. I have 2 parity drives plus 4 data drives in my array. 

2. All disks are functioning normally (no errors).

3. Running parity check so far has reported 50 sync errors corrected.

 

When a sync error is detected and corrected, the only thing modified is the parity, not the data drives, correct?

If a sync error is detected, there is no data loss provided my data drives are still fully intact, correct?

 

Thanks

 

Dale

1 hour ago, dchamb said:

When a sync error is detected and corrected, the only thing modified is the parity, not the data drives, correct?

Correct.

 

You should only run a correcting parity check after a noncorrecting parity check has determined there are sync errors to be corrected, and you are reasonably certain there isn't some other cause of the sync errors. You don't want a bad data disk to cause parity to be changed.

10 minutes ago, trurl said:

Correct.

 

You should only run a correcting parity check after a noncorrecting parity check has determined there are sync errors to be corrected, and you are reasonably certain there isn't some other cause of the sync errors. You don't want a bad data disk to cause parity to be changed.

I was concerned after so many crashes under 6.9.2 with the uncorrected parity check starting automatically and never completing. When I rolled back to 6.8.3 it came up saying parity was valid. I ran a correcting parity check thinking I'd rather be safe than sorry and it reported 50 sync errors. I hope I haven't screwed something up.

A small number of sync errors is typical of unclean shutdown.

Spoke too soon. Up to 14,635 sync errors now

4 hours ago, dchamb said:

came up saying parity was valid

All that really means is that there has been no change of disk assignments since last parity build that would have invalidated parity. It doesn't know from one boot to the next if there have been sync errors.

1 hour ago, dchamb said:

Spoke too soon. Up to 14,635 sync errors now

That might be regarded as a "small" number if it accumulated after many unclean shutdowns.

 

Are there any I/O errors shown in the Errors column on Main - Array Devices for any disks?

 

Attach Diagnostics to your NEXT post in this thread.

Still on 6.8.3 running fine. I invoked the correcting parity check which is now 76.7% complete and has corrected 14637 sync errors. Two CA appdata backup runs have taken place since the parity check started. It looks like both finished successfully. Plex docker is still running. All seems well but I have attached a diagnostic so someone more knowledgeable than me can verify this. 

I am a bit uneasy about having the CA backup run while a parity check is running, mostly because they are competing for resources. If there is a way to prevent it from running during a parity check, please let me know. I have scheduled a correcting parity check once a month on the last day of the month, and have CA backups run every morning at 3AM. 

 

As always I appreciate any input.

One other question: is there anything in the diagnostics that could explain why 6.9.2 will not work for my system?

 

Thanks

 

Dale

tower-diagnostics-20211202-1009.zip