January 21, 20179 yr Parity check takes about ~22 hours....it's on hour #18 and I need to reboot to get video back to my LibreElec VM for movie night. Can I reboot now and have the parity check resume where it left off?
January 21, 20179 yr No, you would waste the 18hrs and have to start all over again, as far as I know.
January 22, 20179 yr It won't pick up where it left off but I've had to do that before. I just start the parity check again. It was suggested as a feature request so it could be added in the future.
January 22, 20179 yr It won't pick up where it left off but I've had to do that before. I just start the parity check again. It was suggested as a feature request so it could be added in the future. The danger is that even if one byte is changed on the drives while the array is paused it will invalidate the parity. It's a good feature but would be risky to use.
January 22, 20179 yr It won't pick up where it left off but I've had to do that before. I just start the parity check again. It was suggested as a feature request so it could be added in the future. The danger is that even if one byte is changed on the drives while the array is paused it will invalidate the parity. It's a good feature but would be risky to use. Not really, because if that byte was part of the section already checked then it'll get updated automatically, and if its not part of the section already checked then it would get checked when the checks resume. Its fundamentally no different than running scheduled full checks once a month.
January 22, 20179 yr It won't pick up where it left off but I've had to do that before. I just start the parity check again. It was suggested as a feature request so it could be added in the future. The danger is that even if one byte is changed on the drives while the array is paused it will invalidate the parity. It's a good feature but would be risky to use. Since unRAID would know if something was written to the disk it only has to invalidate the check in progress and force a complete recheck - I don't see a real risk to the feature if it is implemented that way. Isn't the implication here though (taken to an extreme) that unRaid itself is inherently risky if you don't run a full parity check every time a single byte gets written to the drive(s) because at that point you cannot be 100% sure that you can successfully rebuild a drive because you don't know if the disks and parity all reflect that changed byte?
January 22, 20179 yr It won't pick up where it left off but I've had to do that before. I just start the parity check again. It was suggested as a feature request so it could be added in the future. The danger is that even if one byte is changed on the drives while the array is paused it will invalidate the parity. It's a good feature but would be risky to use. Since unRAID would know if something was written to the disk it only has to invalidate the check in progress and force a complete recheck - I don't see a real risk to the feature if it is implemented that way. Isn't the implication here though (taken to an extreme) that unRaid itself is inherently risky if you don't run a full parity check every time a single byte gets written to the drive(s) because at that point you cannot be 100% sure that you can successfully rebuild a drive because you don't know if the disks and parity all reflect that changed byte? I removed my post because yours made more sense once I read it.
July 6, 20197 yr Sorry to revive an old topic, but this is the first thread that comes up in Google... I am wondering if pause and restart the server has ever been implemented for parity checks... Thanks, craigr
July 6, 20197 yr 15 minutes ago, craigr said: I am wondering if pause and restart the server has ever been implemented for parity checks... Not currently. Pause is implemented, but it won't pick up where it left off if you reboot
July 6, 20197 yr Just now, Squid said: Not currently. Pause is implemented, but it won't pick up where it left off if you reboot That's what I thought. Thanks! craigr
November 22, 20205 yr Hey guys, so if I accidentally restart my array, can I just start the parity again at 0% or do I need to preclear or format again?
November 22, 20205 yr 1 hour ago, Pjrezai said: Hey guys, so if I accidentally restart my array, can I just start the parity again at 0% or do I need to preclear or format again? Need more information. Preclear is used either as a drive testing tool, or to prepare a drive to be added to an array with already valid parity in a new slot. Format writes a blank filesystem to a drive. Neither concept has anything to do with pausing a parity check.
November 22, 20205 yr 52 minutes ago, jonathanm said: Need more information. Preclear is used either as a drive testing tool, or to prepare a drive to be added to an array with already valid parity in a new slot. Format writes a blank filesystem to a drive. Neither concept has anything to do with pausing a parity check. So I was running the first parity build, then i restarted the array, and the parity started from the beginning on the reboot of unraid - is that ok? since it is writing again on a drive that had already had been written on (when I was running the first parity that stopped)
November 22, 20205 yr Community Expert 3 minutes ago, Pjrezai said: So I was running the first parity build, then i restarted the array, and the parity started from the beginning on the reboot of unraid - is that ok? since it is writing again on a drive that had already had been written on (when I was running the first parity that stopped) Yes. Until it gets to the point at which you restarted the array it will simply be over-writing the existing data with the same content (since Unraid will have forgotten you had already started the parity check), and past that point writing the parity information not previously written for the remainder of the drive.
November 22, 20205 yr 7 minutes ago, itimpi said: Yes. Until it gets to the point at which you restarted the array it will simply be over-writing the existing data with the same content (since Unraid will have forgotten you had already started the parity check), and past that point writing the parity information not previously written for the remainder of the drive. Thanks! Just wanted to double check that there wouldn't be an issue that i just restarted the parity creation right on top of the previously failed one
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