I have two 6TB Data Drives in my Server and all my data Drives are 4TB.  I want to increase the size of several of my Data Drives from 4 TB to at least 6TB.  However, when looking on line it appears that 8TB Drives are at about the same price point as the 6TB drives these days.  I know and can put the 8TB data drives in place of the current 4TB drives but if I leave the current 6TB parity drives in place for now the new 8TB drive will only use 6TB.  Now to my question:

 

If I do this now to address my immediate need, and add larger parity drives later, will adding 8TB or 10TB Parity drives later immediately allow access to the remaining 2TB of space on the 8TB Data Drives I add today or will I need to do some other tweaks or adjusting to get the additional space for use?

1 minute ago, Shesakillatwo said:

I know and can put the 8TB data drives in place of the current 4TB drives but if I leave the current 6TB parity drives in place for now the new 8TB drive will only use 6TB.

That's not correct, you'd need to use one of the 8TB drives for parity, parity cannot be smaller than a data drive.

OK, thanks so much.  I must have misinterpreted some things I read on Drive sizes.  I knew you could not have data drive space larger than the Parity drive space but I thought I read if I put a physical drive in for data that is larger than the Parity drive the data drive would only use the amount up to the Parity drive limit.  Thanks for clarifying that this is not possible or correct!

Unraid has the parity swap procedure for upgrading the parity drive to a larger size and then using the old parity drive to replace a data drive.    
 

The alternative is to simply upgrade the parity drive(s) to a larger size and later make changes to the data drives..