In January of this year I started a pair of polls on the Apache Karaf LinkedIn user group, I thought I'd share the results as they stand now. Please note these are unscientific poll results - expect them to be wildly inaccurate as the sample sizes in both polls were very small and limited to the group members on LinkedIn.
The first poll question was "When deploying Apache Karaf what is your most common operating system to target for production use?". LinkedIn only allows up to five options, so I choose five of the major operating systems I've seen in production use. In a sample size of 26 respondents 92% were deploying on Linux, with 8% on a Windows system. I was somewhat surprised to not see any representation for the Unix platforms, and only trace reports of Windows usage. I'm going to issue a follow poll question to further break down the usage of Linux platforms by distribution family, I think it'll be interesting to see if there is a specific distro that Karaf users prefer for their deployments.
The second poll question was "Which version of the JVM do you use most commonly for production deployments of Apache Karaf 2.x? (vendor neutral, 32 and/or 64 bit)". The poll sample size was truly small with only 9 respondents, as such its difficult to make many statements other than Java 6 appears to the popular choice at present.
Again, I must re-iterate that the above polls were un-scientific. The purpose of the above exercise was to create some sort of profile of common Karaf usage - which at this point in time appears to reflect Karaf 2.x running on a Linux based OS using Java 6. Once the Karaf 3.x series of releases are generally available it'll be interesting to reissue the above poll questions and see if the above preferences are maintained or if a shift in deployment pattern occurs.