We have a site with performance issues. And we are looking for advice on low hanging fruit or other strategies that can have a dramatic increase on performance.
The seemingly obvious culprit is massive module bloat with a total of 175 enabled modules. We are aware that this is an architectural flaw however we are not in a position to spend the amount of time necessary to resolve that in any big way. Most of the modules contributing to this bloat are contrib modules.
- We are using memcache for caching and also making use of APC.
- We have already identified so slow DB queries and re engineered some views to get an improvement here.
- We have tuned view and block caching through the site.
We have also applied a few of the common performance and scalability modules including - entity cache - Cache expiration - Cache actions.
Due to other architectural considerations (a 3rd party product working as a reverse proxy) we are not in a position to utilise varnish in a very useful capacity.
The average time out of 5 calls via wget (with a cache clear before each before each call) is about 42.182 seconds on a dev instance. The average time out of 5 calls via wget (with a warm cache) is about 9.43 seconds on a dev instance.
We experience similar slow performance on the staging server. That server also serves a few staging instances of other sites that perform decently. Our sysadmins have configured the databases here so I do not consider the database configuration to be a likely cause of much of our performance issues.
If anyone has experience improving the performance of Drupal sites with large module boat you input is most welcome.