Hey everyone,

I'm considering switching to internal boot but I can't find clear information anywhere (forum or docs) about one specific thing.

Here's my setup:

• Array: 2x 16TB HDD

• Parity: 1x 16TB HDD

• Cache pool: 1x 2TB NVMe

• Motherboard: no M.2 slots left, only a PCIe 4.0 slot (no bifurcation support)
  

My plan is to add a PCIe adapter with a 16GB Intel Optane module for internal boot. Ideally I'd partition it in two: one boot partition (~8GB) + one separate small pool for another use I have in mind.

So far so good: I'm fairly confident this part is doable, and I'm not looking to use the PCIe slot for a larger NVMe (no need for it right now).

The part I can't find any info on:

Is it possible to mirror the internal boot between:

• An 8GB partition on the Optane (with the remaining 8GB used as a separate pool)

• An 8GB partition on my existing 2TB NVMe (with the remaining ~2TB still used as a cache pool)
  

In other words: does internal boot mirroring work across partitions on two different-sized drives? Or does it require full drives?

Thanks in advance, any experience or insight is much appreciated!

33 minutes ago, pfdt said:

1. An 8GB partition on the Optane (with the remaining 8GB used as a separate pool)

2. An 8GB partition on my existing 2TB NVMe (with the remaining ~2TB still used as a cache pool)

It's possible to mirror the boot partition; the remaining space can only be used as a single pool, either an 8GB mirror, or an 8GB+2TB volume without redundancy.

3 hours ago, JorgeB said:

It's possible to mirror the boot partition; the remaining space can only be used as a single pool, either an 8GB mirror, or an 8GB+2TB volume without redundancy.

Thanks for the reply, JorgeB!

I’m still a bit confused though. I want to make sure I understand correctly:

When you say “the remaining space can only be used as a single pool”, does that mean:

• The remaining data partitions (8GB on Optane + ~2TB on NVMe) must be merged into one single pool together?

Or can I create two separate independent pools:

• Pool 1: ~8GB from the Optane data partition

• Pool 2: ~2TB from the 990 EVO data partition (my main cache pool)?

I really need them as two separate pools.

Could you clarify if Unraid 7.3 allows this, or if it forces those partitions into a single pool?

Thanks again!

2 hours ago, pfdt said:

The remaining data partitions (8GB on Optane + ~2TB on NVMe) must be merged into one single pool together?

This is the only option when using the data partition of a mirrored boot pool.

4 minutes ago, JorgeB said:

This is the only option when using the data partition of a mirrored boot pool.

Ok thank you for your answer, now I know !