Grafana is meant to run as a single instance. For monitoring multiple servers, you need to get the metrics into one data store, from which Grafana will read. That's Prometheus' job. These pieces should not be on the same servers that run your product. For HA, you can run two or more Prometheuses as duplicates, so you can switch to another one if the main one is down.

Would the one datasource have a single database with several tables, one for each server? Lets say I am monitoring mysql. Currently I have a `mysql` table in a databse named `telegraf` on each host. Can I combine multiple influx datasources into a single dashboard beacause that would be easiler right now for my current setup?

You handle multiple servers by tagging your metrics with the server id or name. No need to create a table per server.

Each panel in a dashboard points to a specific data source, so you can have multiple data sources in one dashboard.