BitFolk‘s spamd service in London has been a little overloaded in recent times. A lot of the times the backend servers have been complaining that they’re full and some connections were being delayed. As a free service it is challenging to keep it performing perfectly and I only attempt to do so on a “best effort” basis, but hopefully things will be better for a while now as I have finally got around to starting up a new backend server on the most recently installed hardware. I gave it a decent amount of RAM to begin with so hopefully I won’t be facing problems trying to squeeze it in later.
I haven’t yet really considered trying to enforce any sort of “fair usage” policies although that may be an idea, since the top few users tend to use the majority of the resources. I’m pretty sure that they could avoid sending quite so many connections directly through the relatively expensive spamd stage if they were to try other antispam things first, such as insisting on greater RFC compliance, greetpausing, greylisting, stricter use of DNSBLs etc. etc.
I have also noticed that some users are going direct to the backend spamds as opposed to using the load balancer’s service IP. This is bad because the load balancer has an overview of how busy each backend is and tries to direct new connections to the least-used backend. If it then finds that backend is busier than it thought, or worse still, if it’s actually too full to take a new connection, then things get even less efficient. I may have to crack down on this by firewalling off the backends except from the load balancer. Of course I’ll need to make sure that use of the load balancer’s service IP is fully documented, and properly warn people.
I should also investigate dspam at some point.