ejabberd - Comments for "Clustering design and hardware requirements"

Another question

crash2burn — Wed, 24 Jun 2009 04:11:06 +0000

When you add more than two servers, do you need to put every server in the shared node field, and also in the .hosts.erlang file?

It is impossible.

breakevilaxis — Sat, 13 Jun 2009 22:41:48 +0000

If user1 registered at node1, when node1 is down. He can go to node2. But he has to register at node2.
The only benefit of clustering is that when both node1 and node2 are up, user1 at node1 can invite and chat with user2 at node2.

Me, too, wish register at one node of the cluster should automatically register at all nodes of the cluster.

You can try ODBC postgresql

breakevilaxis — Sat, 13 Jun 2009 22:28:53 +0000

I tried but I do not like the way it relies on one master database. And there could be some other problems. You have to test yourself.
All you have to do is to replace mnesia with ODBC postgresql. All nodes connect to one database. When the user register at one node it will register at all nodes because they share the same database. (Also you have to set up Mnesia cluster. The rest of the tables have to be done by Mnesia. This is what I did and this is another thing why I do not like external DB).

I am using internal mnesia now. User has to register at all nodes.

thanks for your reply! If

c0re — Fri, 12 Jun 2009 14:06:43 +0000

thanks for your reply!

If user1 belongs to west-coat.abc.com and if west-coat.abc.com is down due to internet provider, so user1 won't be able to connect to east-coast.abc.com and continue chatting? thinking that user1 is user from internet.
Or i need to make 2 accounts user1@east-coast.abc.com and user1@west-coast.abc.com? But user1 will need to change it's JID before connecting to east-coast.abc.com or west-coast.abc.com and need somehow to synchronize contact list..

This looks not good design for me..

What king of isues are there in clustering over wan?

Cluster & WANs

tlaramie — Fri, 12 Jun 2009 11:26:08 +0000

ejabberd has issues with unstable connections between nodes so connecting between both offices wouldn't work.
You would be better served by using a sub-domain for each branch office ( west-coat.abc.com, east-coast.abc.com ) and facilitating connections using S2S between the two. At each office you could make use of a multi-node cluster and distribute connections through a load balancer or DNS round-robin.
I make use of mnesia (the DB 'engine' that ejabberd uses) as it clusters nicely and find the ODBC implementation for multiple virtual-hosts in ejabberd to be lacking. I would assume that each node would just connect to the same DB server & database and let the DB Server handle the locking and requests handling.