How can I do a volume with 2 separate servers? like I have 2 servers with 300gb, how do I cluster the storage to make 1 volume?

You can't. Only replicas (=copies) are possible on different nodes.

Uhh.. Then what things can I do with a cluster with multiple nodes?

Harvester is a VM solution and Longhorn its (redundant) storage layer. It's intended to create highly available and redundant volumes which continue to work when one server is down for any reason. This is why the default number of replicas is 3. Compare this with raid level 0 and 1. Longhorn does raid 1 (with 3 copies). If you want to have raid 0, you need to look for something different.

Okay so clustering it's just for if one machine fails, another can do the job?

In Harvester, yes. Maybe there is some way to achieve what you want with some Longhorn trick. You should ask in the Longhorn channel! For the other question: You kept the default replica number of 3? Then the volume will never become available... no node to place the 3rd replica.

yes, number of replicas is 3. If i have only 2 nodes, it should be 2?

Yes, 2 or even one if you don't care about redundancy.

okay

If your cluster has only 2 nodes, choosing 2 for the replicas should be enough.

okay

Try it out. I can't, I don't have 2-node-clusters. Did you try to keep the defaults and just change the number of replicas?

yes

I don't know what you're doing. And since you don't post lots of information, the only way is guessing. When you set the storageclass correctly, that's the first step. Next is to create a VM which then allocates a volume from Longhorn automatically.

They should do a tutorial of how to do all of this

its hard for me to keep up with all that has been done

Yeah