About 8 weeks ago I started to migrate some of my services including this xmpp instance to a new server. I could not migrate the previous content management system without doing a very time consuming upgrade but I didn't have any problem with Prosody (the software which provides the xmpp server). Depending on the time of day there are about 500 to 1000 online users and the new server is performing a lot better than the previous one. Why?
The previous (virtual) server was cheap, had 2 CPU cores, 8 GB RAM (if I remember correctly) and 40 GB SSD storage. This was fine for some years but with increasing number of users the performance got a little worse and I was running out of space. I could have switched to a bigger version within the same generation (same CPU, just more cores) to get more storage but this didn't sound like a great deal to me.
Because every time you send a picture or video this server has to keep it for 30 days I got a cheap 100 GB network storage which I attached to the server. Because security and privacy means a lot to me, I encrypted that device using CryFS but the performance was not that great, especially latency and IOPS were bad. When someone sent a huge file, Prosody had problems handling the other connections. I did not want to replace Prosody with for example ejabberd or another xmpp server because usually I was happy with Prosody.
At this time I also had a few other server which got a bit old so I got a more modern (AMD Epyc based) and powerful virtual server. This new server is now hosting some websites, databases and services including this xmpp server. Also I did not need this network attached storage anymore the performance is great again and the multiple outages per day dropped almost to zero.
I hope you can enjoy this service and for the next couple of years this setup should just work fine, 10 CPU cores and 32 GB of RAM should be able to provide a great, secure and privacy friendly way of communication. Thank you all for your trust in this service!