We are planning to introduce real time chat feature in our mobile apps. Ofcourse we would be going the XMPP way.
Can anybody shed some light on stats for maximum number of concurrent users Openfire has supported on EC2 instances (windows server) of different sizes in the real world?
We are looking at numbers ranging from 22500 concurrent users to 75000 concurrent users depending upon growth patterns predicted for app downloads and user adaptability for this new real time chat feature. time range = next 12 months.
From whatever googling I have done so far, it seems Openfire may not be the best bet when it comes to scaling out so can these numbers be supported on a single instance of ec2 over time? ie: we start hosting on smaller instances and keep increasing instance size as load demands.
Ejabbered seemed to be the best option when it comes to scaling out but since we would need to have erlang skills in order to extend it makes ejabbered a difficult choice for us. The other alternate is tigase which is java so we could extend it much easily but if Openfire can work for us for the next 12 months or so by scaling up versus scaling out, we would be happy to use it for now and see how well this new chat feature is embraced. Number one reason being ease of management.
Lastly, if you could help with links on SaaS / PaaS providers for XMPP chat + Push Notifications to mobile devices when user is offline, it would be awesome. We got in touch with quickblox.com but their enterprise offerings appear to be expensive for us at the moment. We want 100% ownership and portability of our data if we go the SaaS / PaaS way.
The numbers you mention should be easily handled by ejabberd.
I am unsure as to how you want to "extend" ejabberd. Multi-user chat and messaging are handled fine by all servers and of course ejabberd. Additionally, if you are thinking of custom protocols, these can be written in your language of choice and connect to ejabberd as an XMPP component.
The only thing you might miss is a web interface (which ejabberd has but it's rather limited), but then again if you expect to manage things through a web UI for an application, you will need to think again ;)