Hi all,

I'd like your thoughts and comments on this idea:

Setup:
- two fault domains = DCs
- connected with 100 GBit, < 1 ms
- 80 NVME SSDs on each side

Goal:
One fault domain can be lost, and then there's still have some redundancy.

Option 1:
Replicated pool with size = 4. This gives me two copies on each side, thus meets the goal. But the efficiency is only 25%.

Option 2:
Erasure coded pool with 2 + 4 scheme. This gives me 3 chunks on each side. If I lose one side, I still have 3 chunks left, where I only need 2. Thus the goal is also met. Efficiency is 33%.


Even though I did a lot of googling, I couldn't find anything about a similar setup. In all profiles, there is k <= m.


What do you think about 2+4, is it a good idea or a bad one, or do I miss something and it doesn't work at all?

In particular: is it possible to recover two data chunks out of 2 coding chunks? As I read the documentation, this should be no problem, just want to confirm.

--
Andre Tann
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