> Battery backup of a single cache still makes it a SPOF
No, it doesn't.
In your scenario, another, prior and unaddressed, failure is required to make NVRAM (and/or other component(s)) a potential single point of failure.
It doesn't make it a...
The recommended setting is to not touch anything.
What link? The official documentation suggests to not configure any settings (i.e. use the default values)...
> For data to be safe, it has to be able to survive 2 failures.
Wrong.
> There are virtually none that will have 3-way replica of every piece of data.
Maybe that's because that isn't necessary?
- 3-way replica isn't needed because arrays can...