March 28, 20233 yr Good day all, I swapped a 3TB drive for a 14TG drive in unRaid. I followed the instructions in the manual to the letter and everything is proceeding as per that document. The question is: The day before the drive upgrade I moved all the data/share off of the 3TB disk and onto another HDD. At this point parity should have known that the data had been moved (or some other indexing system) and when I added in the 14TB drive the rebuild should not have been needed, so why is a rebuild to an empty disk happening? Seems a severe waste of my time as I have other config items to do on the server. A few just like this, so how can I avoid a rebuild for an empty drive?
March 28, 20233 yr Community Expert Solution Parity doesn't know about the data, only bits, it doesn't matter if the disk is empty or completely full, it will take the same time to replace. https://wiki.unraid.net/Parity#How_parity_works
March 28, 20233 yr Community Expert 14 minutes ago, whwunraid said: Good day all, I swapped a 3TB drive for a 14TG drive in unRaid. I followed the instructions in the manual to the letter and everything is proceeding as per that document. The question is: The day before the drive upgrade I moved all the data/share off of the 3TB disk and onto another HDD. At this point parity should have known that the data had been moved (or some other indexing system) and when I added in the 14TB drive the rebuild should not have been needed, so why is a rebuild to an empty disk happening? Seems a severe waste of my time as I have other config items to do on the server. A few just like this, so how can I avoid a rebuild for an empty drive? The answer is that you cannot! A drive with no files on it still has data as far as parity is concerned. It works at the raw sector level and only sectors that are all zeroes would not affect parity. Deleting the current contents does not zero all sectors, and even if it did you would still have all the sectors that are used to maintain the file system information. it sounds as if it would pay you to read the section on how parity works from the Overview in the Unraid documentation.
March 28, 20233 yr Author This would seem simple enough to get around from an OS level if someone wanted to take the time to set it up. Maybe a feature request as I am sure this wastes serious amounts of time for many of our users. Thanks for your help... PS... The documentation for unRaid would be way more helpful with information like this in the appropriate sections. Making the assumption that the documentation makes itself fully transparent to users unfamiliar with the low level details of how a system operates is short sighted. Also might make less traffic on the forums. 😉
March 28, 20233 yr Community Expert 2 minutes ago, whwunraid said: This would seem simple enough to get around from an OS level if someone wanted to take the time to set it up. It would not be, empty disk can still have mostly non zero sectors, so parity would not be valid.
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