Disabled disks pass SMART


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Posted (edited)

PSU died during my move. 

Had to replace the power supply. 

I have a dual parity system and both disabled disks contents are now emulated. 

During the many reboots I have performed the disks became disabled. 

Both short and long SMART test come back without errors for both disks. 

I tried to clear statistics and reboot, however when I reboot the drives are still disabled and contents are emulated. 

How do I tell Unraid that the disk it fine and it should use it. 

 

Maintenance mode?

Anything else than a rebuild?

 

Edited by exist2resist
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Yeah I rebuilt last night, after I started rebuild I had a thought that the config might be a quicker way to accomplish the same. 

 

Having said this the OS might benefit from a "accept disk and reenable" button, or "mark drive as good".

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37 minutes ago, exist2resist said:

Having said this the OS might benefit from a "accept disk and reenable" button, or "mark drive as good

Personally I think that would be too dangerous as users would tend to blindly click it and then not make sure that parity is correct meaning any future recovery could result in corruption at best.    Going via the New Config tool does at least mean that a few more steps are required so a little more caution is likely from users.

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2 hours ago, exist2resist said:

Having said this the OS might benefit from a "accept disk and reenable" button, or "mark drive as good".

There are very few instances where this is true.

 

Unraid disables a disk AFTER a write to it failed. That means that data that was sent to the disk didn't get written to that disabled disk, instead it only exists on the emulated copy. This write could be something inconsequential or an overwrite of existing data, or it may be a critical write that if discarded would mean a corrupted file or worse, a corrupted file system.

 

The "safest" thing to do would be to do a full binary compare of the disabled disk and the emulated content, display the difference and allow the user to choose which copy is most accurate. That would not be a trivial process, and would have very little benefit over what's currently available, where you can browse the emulated disk and if it looks good, rebuild that content to the physical disk.

 

The shortcut of just "mark drive as good" means you need a full correcting parity check to be sure all the bits that got written to the emulated disk that you just discarded are updated to keep parity in sync. It typically takes just as long to do a full parity check as it does to rebuild a disk, so you aren't saving any time.

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4 hours ago, jonathanm said:

There are very few instances where this is true.

 

Unraid disables a disk AFTER a write to it failed...

Actually it disabled the disk on read error for me not write error. I have had this happen before.

 

6 hours ago, itimpi said:

Personally I think that would be too dangerous as users would tend to blindly click it and then not make sure that parity is correct meaning any future recovery could result in corruption at best.    Going via the New Config tool does at least mean that a few more steps are required so a little more caution is likely from users.

 Makes sense. 

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8 minutes ago, exist2resist said:

Actually it disabled the disk on read error for me not write error. I have had this happen before.

It is always a write error that disables a disk, although a read error can trigger a write error if as a result parity is used to reconstruct what should be on a sector and Unraid then tries to write that back to correct the read error, and that write then fails.

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17 minutes ago, exist2resist said:

Actually it disabled the disk on read error for me not write error.

No, if the subsequent write after the read error succeeds, the disk is not disabled, but the disk error column is incremented. It is ONLY disabled if a write fails, as itimpi said,

 

Read errors are corrected by writing the parity emulated data back to that sector.

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