That has emerged as the question, or at least a major factor in determining whether open source software works in the enterprise systems management market.

The three open source players that have managed mid-market and enterprise customer growth — GroundWork Open Source, Hyperic and Zenoss — all base their products, both community and enteprise versions, on software licensed under the GNU General Public License (GPL).

The three systems management ventures that have faltered recently — Levanta, Open Country and Qlusters — did not use GPL licensing. Levanta and Open Country did not even offer community or free versions. While Qlusters opened its QRM software in 2006, it did not emphasize its free version, which is now in the hands of the openQRM developer community. Open Country and Qlusters did base their products on open source software that was licensed under the Mozilla Public License with attribution. This is not to say MPL does not work in the enterprise (see systems management project Ziptie, licensed under the MPL). However, when looking at these six companies and considering their differences, the GPL licensing stands out.

Other prominent factors are the functionality focus (monitoring seems to be a gap in current offerings and competition, compared to provisioning, patching and other systems management subcategories) and interoperability with and support of Windows and other proprietary software.

This is not to say GPL licensing + monitoring = enterprise systems management revenue. There are other examples of ventures based on open source software, such as OpenESM, that are both GPL and centered on monitoring, yet never took off. However, when we look at the newest open source systems management ventures — OpenNMS Group, Nagios Enterprises and Paglo — we see that these community-driven commercial plays are sticking with what works: the GPL.