Posted by playfulwolf on March 31, 2010 at 2:25am
Using Authcache (cacherouter memcache) for all user roles, registered AND anonymous (drupal core cache of course disabled) and using Boost at the same time. APC is on server installed also, but not used with cacherouter.
Is Boost useful and doing its job under these circumstances??? Memcached daemon is acting kind of strange if boost crawler is disabled - it spikes to almost 100% cpu on pageview, page loads are high even when visiting the same page etc, RAM usage just few megs of available 128, some APC memory is also free.
Comments
Understanding of Authcache, Memcache and Boost...
Authcache is for caching authenicated user sessions under memcached, however it has the limitation of not being able to be clustered. Memcached (by itself) supports unauthenicated user sessions. Boost is strictly geared for static content, not dynamic.
Something else you need to watch for when using memcache is that when keys are over 250 bytes, they get corrupted, thus never get cached. I recommend looking at this thread and patch for existing issues, etc.
Memcache API and Integration :: long keys get truncated
http://drupal.org/node/525400
One option you might want to consider using a multi-memcached configuration which allows breaking up each cache table into seperate memcache 'bins'. If you have multiple servers, you can then cluster the memcached bins, which will give greater flexability.
Authcache :: Authcache and memcache module integration
http://drupal.org/node/495478#comment-1819338
Correction
Minor but important correction ...
The key can be more than 250 bytes if the site used Unicode or special characters in the URL.
When this happens, cache clashes will happen. This means that the same result will be returned for different URLs, not that they will not get cached.
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While authcache was designed
While authcache was designed to serve pages for authenticated users, is there a good reason NOT to use is as an alternative to boost for non authenticated users? It seems to work just fine and means you have one less module to configure and worry about. Additionally it still supports the statistics module out of the box, which is great for sites with popular content blocks etc.
I'm not sure if authcache is
I'm not sure if authcache is really "one less module to configure and worry about", since you not only have to always check if authcache doesn't break something in the site because of its "one cache per role" logic, but also you need to (I know, it's recommended and not required) add "cache handler module", like Cache Router or Memcache API and Integration to get better results.
You can get far better results, without any side effects, by using Boost and Memcache API and Integration (or Cache) directly. BTW: Boost disables native drupal caching, but it is enabled (and hardcoded) in Aegir by default -
$conf['cache'] = 1;, so you can still use static files for anonymous visitors from Boost and fast cache (memcache) for logged in users.As for statistics, Boost supports it and it works without issues (we are using it on many sites) - just enable "Boost: AJAX core statistics" block, as explained here: http://drupal.org/node/545908#blocks.
Furthermore, the biggest difference is: authcache still uses PHP to serve static files (and doesn't allow to configure gzipping them or not), while Boost allows to serve them directly by the web server. Because of this one difference alone, it is hard to consider authcache as a Boost alternative, I think.
gzip
pre-compressed content really speeds things up according to the latest benchmarks
http://drupal.org/node/101227#comment-3176382
Link above claims
Maybe it is the case with
Maybe it is the case with Apache, but I tried it with Nginx many times and can't see any visible difference at speed/system load when serving pre-compressed files generated by Boost with Nginx as-is and when compressing them on the fly by Nginx, so I prefer simpler Nginx configuration for Boost. But if someone knows about good benchmarks showing real difference, it would be interesting to compare the results.
Perhaps Nginx is also caching
Perhaps Nginx is also caching files after it compresses them? That's how Lighty's compression module works.
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