scaling out djabberd

[Martin Atkins]

Haseeb Abdul Qadir wrote:
> The djabberd main page mentions that djabberd can be scaled out by 
> inter-connecting modes together. Does anyone have examples on how to do 
> this? I'd like to setup 2 djabberd servers for load balancing a vhost - 
> similar to livejournal's config as shown here: 
> http://aero.sarang.net/blog/2007/11/24/livejournal.png .
> 

I may be wrong, since I've not been following what LJ has been doing 
with DJabberd, but I believe LiveJournal currently only has a single 
active DJabberd node. That extra node shown in the diagram may 
illustrate a failover node to switch to if the active one goes down.

There is currently no clustering support in core DJabberd. While there 
are some classes that could be fleshed out to support it, no-one 
actually ever designed clustering support and implemented it.

LiveJournal actually does most of the heavy-lifting in Gearman workers, 
so their DJabberd node is relatively cheap and so they can scale the 
expensive work -- loading rosters, etc -- by adding more Gearman workers 
to the pool.