Scalability has always been a hallmark of Jabber XCP, in fact it was the primary reason we forked away from the jabberd open source code back in 2000 and why we have almost no code in common with that project today.

Scale, followed by extensibility, and broad interoperability were the driving forces for our largest customers back then. When we delivered the real-time messaging service for Disney’s Go network back in the day, we were tops in scalability by just about every measure. Today, scale remains a key issue for really big customers, including many carriers, which is why we just completed some heavy load and scalability testing.

When we stepped into the test center recently, we already knew we could scale, with one telecom customer having already certified Jabber XCP as capable of supporting 100,000 concurrent users on a single box. We walked out a few weeks later in awe of our server and the 1,020,000 concurrent users we have now been independently certified as being able to support across a single domain.

For this test, the baseline was 420,000 concurrent users on a single T2000. Each concurrent user was programmed to methodically exchange messages, presence, and subscription requests to simulate likely scenarios in a carrier environment. At the top end of this test we had 1.8 million registered users with an average roster size of 30 . Each concurrent user performed an action every 120 seconds for the duration of the test, resulting in more than 15,000 delivered stanzas per second…these were not stagnant accounts.

What amazed even us was that as the scale of the test increased, the efficiency of Jabber XCP also increased while CPU utilization decreased significantly. For Jabber, Inc., this furthers our hypothesis that the scale of Jabber XCP - even in a single domain - has no known limit, clearly reaffirming that when it comes to scalability, Jabber XCP is in a class by itself.

If you’re interested, I’m happy to answer publicly or privately any questions about our methodology and results, along with the specific hardware requirements necessary to achieve supreme scale using Jabber XCP.

Please post your questions here as comments to this post or email me personally at ckaes AT jabber.com.