How many drives vs. 1 parity? Dual parity in the future?

[plantsandbinary]

Hi I've read the wiki but there's no mention of how many drives you can have alongside a single parity drive.

 

Currently I have 4x4TB drives, with 1 of them being for parity. I'm thinking about adding another 8 of these drives because I can buy them in bulk for only $50 each.

 

So what's the max drive limitation covered by a single parity drive and when would I need to add another parity drive?

Edited October 14, 2018 by plantsandbinary

[JorgeB]

2 minutes ago, plantsandbinary said:

how many drives you can have alongside a single parity drive.

Current max is 28 with a Pro license.

 

2 minutes ago, plantsandbinary said:

The point is, Unraid doesn't seem to support double parity

Incorrect, Unraid supports dual parity since v6.2

[Frank1940]

10 minutes ago, plantsandbinary said:

So what's the max drive limitation covered by a single parity drive and when would I need to add another parity drive?

The is no rule about when you should move from single parity to dual parity.  It depends of your Risk Tolerance.  This thread will provide you with a good approximation of the risks involved and some factors that you may not have even thought about:

 

     https://forums.unraid.net/topic/50504-dual-or-single-parity-its-your-choice/