Best use of Optane 905Ps in Unraid

[werkkrew]

I bought two 1.5tb Optane 905P's recently and my plan is to use them for my docker/appdata/vm storage on Unraid.

I am torn between single device pools running XFS on them and taking the risk of the loss of redundancy for the sake of performance or running a ZFS mirror with them. My other "cache" that I use as a basic unraid write cache is a pair of Samsung 990 Pro's in a ZFS mirror. My main unraid "array" is the standard Unraid array with drives formatted with XFS. I have no plan to go to ZFS for my array and use the Optanes for SLOG or L2ARC or anything like that.

I bought the Optane to bring raw performance to any VM/container running on it, so I am wondering how to best get the most performance these drives can deliver. I am particularly interested in getting my Plex sqlite db to be super responsive as well as have Immich perform better. I am hoping to see a level of performance that justifies their cost over just getting some more consumer NAND based ssds.

If I go with ZFS are there any specific tuning options I should use or consider? Unraid by default formats all drives with MBR, 1MB Alignment. Should I change to GPT? Is 1MB alignment ok?

 

[nexox]

The partition table type won't affect performance, and I wouldn't even use one. Optane isn't as sensitive to alignment as NAND, any multiple of 4k should be fine (or just don't use a partition table and get zero alignment by default.)

If you want a mirror with the least performance impact you want mdraid with XFS on top, there will still be some performance penalty, but not as much as other options.