Any help is much appreciated, Unraid newb for the most part here.

Getting these errors in syslog: kernel: md: disk0 read error, sector=736711744

Fix Common Problems says:

Can it be determined if the Parity disk is bad or it is the cabling?

If it is a bad disk should I wait to replace it because I am in the process of replacing a data disk and it is still preclearing (taking forEVER)?

If it is a cabling issue is it recommended to just replace the cable? I have checked that the connection is tight.

Diagnostics attached.

TIA

descartes-smart-20251223-0815.zip

2 minutes ago, Willion said:

Diagnostics attached.

No that is just the SMART report for a single drive.

Attach Diagnostics ZIP to your NEXT post in this thread.

Attached wrong file on initial post, here is the Diagnostics file attached. Thank you trurl.

descartes-diagnostics-20251223-0724.zip

It's not logged as a disk problem, and SMART looks OK, so most likely it's a power/connection issue.

Your other FCP error is your log filling up. Take a look at your syslog and see if you can figure out what other machine on your network is causing all those log entries and see if you can make it stop.

Simplest way to fix your log full problem is to reboot.

How do I fix a power/connection issue? FYI, the power supply was recently replaced because it went bad.

Check connections, power and SATA, both ends, including splitters.

Make sure there is slack in cables so nothing is pulling on them at the connection.

Don't bundle data (SATA) cables.

Ideally, no more than 4 drives per PSU cable. MOLEX-SATA splitters are better than SATA-SATA splitters.

Try replacing cable.

I should have mentioned that I have at least 5,000 of those read errors, maybe more because my syslog was full.

I have increased my syslog size and it will be permanent upon the next reboot.

Dec 23 07:00:46 Descartes kernel: md: disk0 read error, sector=736716856
Dec 23 07:00:46 Descartes kernel: md: disk0 read error, sector=736716864
Dec 23 07:00:46 Descartes kernel: md: disk0 read error, sector=736716872
Dec 23 07:00:46 Descartes kernel: md: disk0 read error, sector=736716880
Dec 23 07:00:46 Descartes kernel: md: disk0 read error, sector=736716888
Dec 23 07:00:46 Descartes kernel: md: disk0 read error, sector=736716896
Dec 23 07:00:46 Descartes kernel: md: disk0 read error, sector=736716904

I would be checking the cabling very carefully! SATA connectors (both power and data) are very susceptible to loose connections. Inspect and re-seat every end. There should be a perceptible amount of friction as the connector is seated (and unseated).

Then double check/inspect your work as even a very slight pull on a cable can unseat it slightly.