January 22, 20233 yr Hello, helpful community. I don't have any problems with my UnRaid system at the moment. I just have a couple questions about the parity process. Right now this is how I have my parity check set up. This will start the parity check at midnight on Tuesday of the second week of every other month and not stop until completed. If I use the cumulative parity check feature and set it up as follows, what will change? My understanding is it will start just like before at midnight on Tuesday of the second week of every other month. With these settings will it start at 12:00am and continue for 10 hours and stop at 10:00am and resume Wednesday at 12:00am and continue that way until finished? Is there any downside to this other than taking multiple days to finish? Could it hurt the integrity of the parity check? My other two questions are related to my fear of something bad always happening since I don't know a whole lot about computers. When a parity check is in process, is the process robust? If I write to my disk array during the parity check, is it possible for it to mess up the check? I assume the performance drop during the parity check is for a good reason, so it doesn't mess up anything. What about during a disk rebuild? (if I take out 8TB disk 4 and replace it with 12TB) Being emulated, it would be preferred to not write to the array, but what if you do? Any chance of messing up the rebuild or does UnRAID know how to handle it? It seems like so much work for the system to write and read from parity plus read from the remaining disks and write to a disk or even write to an emulated disk. Not sure if that's how it works. Right now when I rebuild a drive, I disable the mover and only allow Plex to run. During a parity check, I don't disable the mover. Should I? Thanks for all your support. Sorry for so many questions. I just don't want to stress the system if it's not necessary.
January 22, 20233 yr Community Expert 3 minutes ago, Cupid said: start at 12:00am and continue for 10 hours and stop at 10:00am and resume Wednesday at 12:00am and continue that way until finished? correct 4 minutes ago, Cupid said: Is there any downside to this other than taking multiple days to finish? Could it hurt the integrity of the parity check? no 4 minutes ago, Cupid said: If I write to my disk array during the parity check, is it possible for it to mess up the check? No. 5 minutes ago, Cupid said: performance drop during the parity check is for a good reason, so it doesn't mess up anything. Performance drop is simply due to trying to access different parts of different disks for the different processes. Parity could be working in one place, and other read/writes would be in a different place. Platters have to rotate and read/write heads have to move. While these mechanical things are pretty fast, they are very slow compared to solid state electronics. I occasionally use my server for small read/writes during checks and rebuilds, but avoid large data transfers during these times simply because it slows everything down. File access slows down parity checks, parity checks slows down file access. Almost all due to the mechanical things happening. Our computers are much faster than they were, but our data is larger than it was, so some things can still take many hours.
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