Hi

Why has Unraid suddenly disabled my parity disk ?

 

Where is the Unraid syslog placed ? cant find it in v6....

Go to tools, click diagnostics, attach zip.

Thanks Johnnie

 

Syslog attached

 

syslog.txt

For V6 it's always best to attach the complete diagnostics.zip, much more info.

Full diagnostic file

tower-diagnostics-20160427-1113.zip

Parity (and all other disks) look ok, syslog is after rebooting so it doesn't show what happened.

 

Though the disk SMART looks healthy, it can still be a bad disk, but more likely is a bad cable/connection, I would start by replacing the parity disk cables and rebuild parity, if it fails again in the near future it's probably a bad disk.

Ok - I'll replace cable and see.

 

Thx

Parity disk still disaled with a new cable. Do I need to enable it somewhere ?

Stop array, unassign parity disk, start array, stop array, re-assign parity disk, start array to begin parity sync.

Ahh thx again

unRAID disables a disk when a write to it fails. Any disk that has been disabled, whether parity or data, will have to be rebuilt because its contents are no longer valid, but the valid data required to rebuild it is still in the array assuming only one (or two with dual parity) disk has been disabled.

unRAID disables a disk when a write to it fails. Any disk that has been disabled, whether parity or data, will have to be rebuilt because its contents are no longer valid, but the valid data required to rebuild it is still in the array assuming only one (or two with dual parity) disk has been disabled.

Disable, I understand but is it too drastic to require a rebuild every time? Is there anyway to avoid it?

I mean all it can be is just a wonky cable.

unRAID disables a disk when a write to it fails. Any disk that has been disabled, whether parity or data, will have to be rebuilt because its contents are no longer valid, but the valid data required to rebuild it is still in the array assuming only one (or two with dual parity) disk has been disabled.

Disable, I understand but is it too drastic to require a rebuild every time? Is there anyway to avoid it?

I mean all it can be is just a wonky cable.

 

Yeah, but even if it was "just a wonky cable" the contents of the drive that could not be written to will still be out of sync with the rest of the array...

unRAID disables a disk when a write to it fails. Any disk that has been disabled, whether parity or data, will have to be rebuilt because its contents are no longer valid, but the valid data required to rebuild it is still in the array assuming only one (or two with dual parity) disk has been disabled.

Disable, I understand but is it too drastic to require a rebuild every time? Is there anyway to avoid it?

I mean all it can be is just a wonky cable.

 

Yeah, but even if it was "just a wonky cable" the contents of the drive that could not be written to will still be out of sync with the rest of the array...

Exactly. After a disk is disabled, unRAID will no longer try to read or write that disk.

 

In the case of a parity disk disabled, the write to parity that failed caused the disk to be disabled. After parity was disabled, no further writes were made to parity even though additional writes to data can happen. You have no way of knowing how much parity is now off. Parity must be rebuilt.

 

In the case of a data disk disabled, the write to the disk that failed caused the disk to be disabled. But parity was updated so that failed write can be recovered. After the disk was disabled, no further writes are made to the data disk, but parity is still updated so any additional writes for that disk can be recovered. The data disk must be rebuilt to recover all the writes that were missed.

 

And note that failed data disk writes may mean something much more serious than just a file is incomplete. The filesystem that keeps track of the files is also data on the disk and filesystem writes may also have been missed. If it is not rebuilt you could have filesystem corruption in addition to bad files.

 

So considering all this I think you will agree that a rebuild is not too drastic.