I've ran an Unraid install on my old desktop hardware for ~2 years now and I love it. I initially used it to store data, but overtime bloated it with VMs/dockers. It's at the point now I'd like to have a separate machine with more compute to run these applications. I recently purchased a R730 which I plan to offload the applications onto and use the original Unraid machine for almost solely data storage.
With that said, I would like to use an all SSD array on the R730 to keep whatever I run on it, "fast". I've known for a long time ever since I first started research Unraid SSDs ""cannot"" be used in the storage pool(s) and only as cache drives. I've also read 10's of posts that seem to kind of contradict that. I really can't find a clear answer that outlines when and if they are used what you are giving up, how to do it "the best", etc. Just little tidbits of information here and there that don't always match up. Provided I've seen moderator level members mention they've built all SSD machines for clients and themselves, I have to assume there is some reasonable way to do this.
So the best I can tell (from limetech's response) is that when I select a drive I need to check its TRIM command type if its "Deterministic read zeros after TRIM" (DZ_TRIM) then that's the best outcome, "Deterministic read data after TRIM" (DX_TRIM) then that's "ok", and otherwise the drive probably shouldn't be used. Further, and I doubt this makes sense, I think I would just stay away from the SSDs listed as having some issue on the wikipedia TRIM page. What else can I do prior to actually setting up the array to ensure the SSDs I purchase are "good to use"?
I've also seen some interesting solutions where users have no parity drive in the pool which somehow makes the situation better. How would this make the issue better? I've also seen solutions where, from what I can tell, users have a small HDD based storage pool and then utilize a large SSD cache pool and just run all the applications from there. Is there a good post or documentation on how to implement such a solution?
And just overall, is there a Limetech specific page/documentation outlining any of this? If and when SSDs can be used as storage?