I just started parity check and one of the discs had write errors. Now the disk is disabled and webgui shows "no device" after I took the array offline.

 

I had checked parity 11 days ago, but was just going to upgrade a disk.

 

Can I just replace the disk with a new one and run rebuild (i.e. can i trust parity)? I checked the cables connections and they seem ok.

 

EDIT: The failed disk is smaller that the replacement, so I don't have problems just replacing it and rebuild, if that is ok. I can deal with the failed disk later.

syslog-2013-12-03.zip

This is cause for concern:

Dec  3 19:50:12 Tower kernel: md: correcting parity, sector=64785216

 

Replace disk 4 and rebuild. Then run a parity check. Then run reiserfsck check on disk 4. Report any anomalies. Meanwhile, examine the failed disk on a PC. You will need a driver, e.g yareg, or better still, recovery software.

This is cause for concern:

Dec  3 19:50:12 Tower kernel: md: correcting parity, sector=64785216

 

Replace disk 4 and rebuild. Then run a parity check. Then run reiserfsck check on disk 4. Report any anomalies. Meanwhile, examine the failed disk on a PC. You will need a driver, e.g yareg, or better still, recovery software.

 

Thanks, will do!

 

BTW, why does parity check write data on disks?

It's attempting to write the correct value back to the location after reading all of the other disks. This often fixes the read problem.

BTW, why does parity check write data on disks?

 

Normally it does not.  But if it encounters a read error on a disk, it reconstructs the proper data from the other disks, then rewrites the sector with the error.  Most of the time this will resolve the error [if, for example, the disk had a failed sector, SMART will remap it and the write to the new sector will succeed].    But if there's an error with the write, the disk is disabled -- which is what happened to you here.

 

Thanks, that makes sense.

 

BUT... I replaced the drive with a new one, but the disk 4 is still "not installed" and the new drive is not in the dropbox.

 

I have changed the power cord, no change... I switched the connectors on the supermicro controller... no go... I even unplugged one of the mobo sata connectors and connected the new drive to that, but no.... the 4th drive seems not to be recornized by the server.

 

EDIT: On boot I got "PD Not Ready or Unknown Device" and took out the replacement and tried on my PC and it's DOA. My first time with any HDD. Damn! 

The parity was correct and rebuild + check went fine.

 

The old drive seemed to have reallocated sectors pending. It's a WD (warranty valid till 12/2014). Does this qualify for RMA?

 

 

The parity was correct and rebuild + check went fine.

 

The old drive seemed to have reallocated sectors pending. It's a WD (warranty valid till 12/2014). Does this qualify for RMA?

 

If it's still under warranty it will qualify for an RMA. Most drive manufacturers will RMA a drive whether there is actually something wrong with it or not as long as it's under warranty.

Nice! Thanks!

 

 

 

The parity was correct and rebuild + check went fine.

 

The old drive seemed to have reallocated sectors pending. It's a WD (warranty valid till 12/2014). Does this qualify for RMA?

 

Have your tried running pre-clear? Pre-clear should resolve any pending sectors. But If the reallocated count is greater than 5 then RMA.