Hello Folks,

 

After a recent non-correcting parity check, noticed some read errors in the parity disk column via the web interface, but no reported parity sync issues. Checked the syslog, and saw some 'handle_stripe read errors'. Ran a second non-correcting parity check, and the parity disk read errors increased, but again no reported parity sync issues.

 

I ran short and long SMART tests on the parity drive; short tests ran OK, but both long tests seemed to stop soon after having a read error with 90% or the test remaining. The only SMART reporting data that caught my attention was the Current_Pending_Sector count of 45; I checked that same drive 3 months ago (I still have the SMART report) and the Current_Pending_Sector was 0.

 

My question is, if the parity disk is having read errors, does that invalidate the parity sync check?

 

If unRAID can't read the data on the parity drive, how can it make a decision about whether or not the data on the drives is correct?

 

How can I be sure that data drives can be trusted to build parity on a new replacement parity drive?

 

System set up is in my sig and I've included my syslog and SMART report for the parity drive.

 

Thanks for the assistance and let me know if I left anything out,

 

-L

Parity_Check_Syslog_2012-11-13.zip

SMART_Report_Parity_Disk.zip

Do you have reason to believe that data on any drive is invalid other than parity? If not yank the suspect drive and rebuild parity rather than waiting around for another possible drive failure....

Thanks for the help BLKMGK.

 

I don't have any reason to believe parity is not valid, I was just wondering about the validity of the parity checks. Looks like I need to understand parity a bit more

 

I'm going to go ahead and replace the parity drive.

 

I do have one more question though I'm hoping someone can answer:

 

I have a new 3TB 7200 Seagate drive that went through 3 pre-clears, but I needed to transfer to about 500 GBs between computers and formatted it for use on a desktop computer.  Do I need to run another pre-clear on it before I use it as a parity drive for my unRAID setup?

 

Thanks for the advice,

 

-L

 

No. Not for parity.