GrapheneOS dev account seems to disagree about the scalability issue being limited to very large instances. Due to the way how Matrix works, even activity on other servers can generate events at your server, particularly when you have joined busy channels.
Not a software engineer, but a server software that collapses at only 100 events per second on modern hardware sounds pretty bad to me.
There are two different performance issues here. One is the stuff that Graphene is talking about, which affects all server sizes, and we are trying to fund work on to fix in FOSS Synapse - see https://news.ycombinator.com/item?id=42752847.
Entirely separately: there are bottlenecks you hit if you try to run a 100K+ user server. Synapse Pro fixes those bottlenecks, and the idea is the $ derived from that can then fund the broader FOSS improvements, which otherwise are starved of funding.
GrapheneOS dev account seems to disagree about the scalability issue being limited to very large instances. Due to the way how Matrix works, even activity on other servers can generate events at your server, particularly when you have joined busy channels.
Not a software engineer, but a server software that collapses at only 100 events per second on modern hardware sounds pretty bad to me.