I would prefer much more to have something hosted by me and being open source at the same time (I'm looking at you, Splunk). I'm desperate enough to write such thing myself (and I'm already doing some research on indexing semi-structured data), even if it would turn out not-too-scalable (I only have ~1.5GB/day of uncompressed logs), but I'm scared by the need of tolerance for abrupt shutdowns and hitting a free disk space limit, i.e., database recoverability.