I've been able to make good utilization of Linode's multiple cores for our Sphinx server (http://sphinxsearch.com/)

In sphinx's config files, its super easy to split an index up into 4 parts, and then assign each partial index to one core.

Doing this, we find that all 4 cores are utilized nicely (>50%) almost all of the time. I feel like we're getting a really good value out of that machine.

AirBnB has a good writeup on this config: http://nerds.airbnb.com/how-we-improved-search-performance-b...