Best setup for SSD and HDD combo

[SamC]

Sorry, for the 2nd request for help in an evening!

So i've got 4x 2tb HDD and 4x 2tb SSDs for my setup. Plus a 1tb nvme drive i was gonna use as cache.

Initially i was just gonna stuff all the drives in the array and use 1 or 2 of the HDDs as the parity (because of supposed SSD parity issues).
But now i'm wondering whether i'm better off using the HDDs in the array and setting up the SSDs in a pool. Is there an issue with having SSDs as parity in a btrfs raid 5 setup, if that's the route i went down for the pool?

How would you set this up? Thanks

[JorgeB]

8 hours ago, SamC said:

Is there an issue with having SSDs as parity in a btrfs raid 5 setup, if that's the route i went down for the pool?

There’s no dedicated parity in pools, and perfectly fine to use SSDs, but note that btrfs raid5/6 is still considered experimental, I use it but there are some known issues, so make sure you have good backups of anything important. 

[SamC]

2 hours ago, JorgeB said:

There’s no dedicated parity in pools, and perfectly fine to use SSDs, but note that btrfs raid5/6 is still considered experimental, I use it but there are some known issues, so make sure you have good backups of anything important. 

Yeah, that's what i meant, got my terminology wrong. I meant is there an issue using SSDs for btrfs raid 5/6? I get it's still experimental in general

[JorgeB]

4 minutes ago, SamC said:

I meant is there an issue using SSDs for btrfs raid 5/6?

No, they are faster than if you use HDDs and trim works fine, and as long as you have stable hardware it should be fine, I have like 15 raid5 btrfs pools between my servers, some of them running for 4 or 5 years without any problems, but like mentioned there are still some known issues.