After a lot of mysql tunings, I intend to use Varnish as the last resort to improve my D6 site's performance which has become increasingly sluggish. I realized that Varnish will not work with D6. And due to lack of som contrib modules, I still can not migrate to Drupal 7 which, as I understand, makes migration to Pressflow pretty redundant.
I am using nginx + php-fpm as web server and try to avoid Apache at any cost. This approach has of course its downside, for example I could not make use of Boost module. Now my question is that whether pressflow works with my web server configuration? and whether migration is a good idea performance-wise? And Pressflow suites me, where can I find docs to make a smooth migration on Ubuntu server.
Thanks for your suggestions.