Can I safely transfer to my array during a parity check\rebuild?


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I had my array set up haphazardly because I was excited to give unraid a try and had a bunch of older random drives I thought I could put to better use than sitting in a drawer. 


I had a 4tb parity drive, a single 4tb data drive, a 750, 640, and 500gb data drive, and a 250gb cache drive. Everything was ok and parity was good.

 

Today I added another 4tb for parity and another 4tb data but because of a limited number of sata power connectors from my PSU i had to lose the older and smaller 500gb drive. It only had about 4gb used on it by the array. None of that data I would consider critical. If I lose it I don't care that much. I'd rather not, but its whatever. 

 

So after restarting the array once these changes were made it of course started a parity\data rebuild. It's looking like it will take another 2 days or so to complete. I think this is about right? I think I read that 2nd parity means more reliable recovery, but it takes more time to do the parity check, correct?

 

My real question is, while this is all going on, can I safely move files from my gaming PC to my array or will that hose the parity\rebuild process?

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In principle the time for a parity check is primarily determined by the size of the largest parity drive - not by whether you have single or dual parity.    Having said that you can also have other bottlenecks such as CPU or disk controller bandwidth.

 

you CAN write new files to the Unraid server while parity is being built but you will find that you take a performance hit while doing so both on the speed of file transfer and on the speed of the parity check due to disk contention between the two activities.   You have to decide if the trade-offs are acceptable.   You could always initially try a small transfer as a trial.

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Hah, I am sure I have all sorts of bottlenecks. I didn't build this with any kind of optimization in mind. I wanted to try something new and had a bunch of fairly old hardware I wanted to put to some use. People give me old systems all the time when I work on their PC's. I'm not at all surprised that it is taking a while. This is going along with an AMD Athalon X64 4000+. Dual core from 2004. I plan to get better hardware but for now this is good enough.

 

I'll try your suggestion of smaller transfers to see how bad the hit is. I can wait. I just didn't want to break anything. Thank you very much for your reply.

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