I have just given up on hosting Matrix altogether. Synapse is a total pain. I'm back on XMPP. 😉
Discussion
It's actually the first big issue I am having with Dendrite, basically ever. o.o I've been quite satisfied with it. ^^
Synapse on the other hand... i stopped counting how many do-overs I have had -.-
However, it seems that development on Dendrite has slowed down somewhat, makes me a little worried.
I host a Synapse node with >400 users. The database (without media) is currently >500 GBytes. The handling of state in Synapse is just broken (the state table alone is over 370 GBytes big).
I hope for you that Dendrite behaves better in regard of DB size. :)
matrix.data.haus is sunsetting in 14 days now. I've set up a small Prosody XMPP server for me and my friends instead. Seems to work a lot faster.