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Can I add parity disk after the copy?

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Hello, new member, nice to meet you.


I'm trying to build my new server with unRAID v4.7 and I have a question.


I have 2x WD 1,5 TB EADS (currently preclearing).

I have a Seagate XT 2 TB drive that has the backup data of the first two drives.


I know that the largest drive has to be the parity drive.


So, can I build my server without parity (using only the first WD drives) in order to copy the data from the largest Seagate onto the WD drives, through my windows pc?

And then I would preclear the Seagate drive and add it to my unRAID server as the parity drive...

Is this possible?


And what's wrong if there's no parity drive in the server, besides protection reasons?


Thank you...

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You can add the parity drive after copying all data to the data disks first. This way you  are also getting more speed when copying.

You don't have to use a parity disk with unraid, but then you are not protected against hard disk fails.

You can add parity after you copy the data, but if you do, you run the risk of a bad disk sector on the destination data disk corrupting your data.


If parity is in place, then each destination disk sector is first read, and then written.  This triggers the SMART firmware on the disk if you have an unreadable sector.

If parity is not installed, the first time you'll know of an unreadable sector is when you initially calculate parity, and by then, you may not be able to read a file you wrote.


So... you can have the faster speed of the initial copy with no parity disk installed, or better integrity of your data with one installed.... Your choice...


Joe L.

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