I see that the cyrus-imap-2.2 branch already uses skiplist as the default format. Does this recomendation also apply to the 2.1 branch or was this due to some code change between 2.1 and 2.2?
Here are some notes which might help you in deciding which database backend to use and why. Recommendations are offered for both 2.1 and 2.2 releases..
http://acs-wiki.andrew.cmu.edu/twiki/bin/view/Cyrus/WhatDatabaseBackend
