What is external page caching in Drupal

开发者_高级运维What is external page caching in Drupal? How is it different from the intrinsic caching mechanism in Drupal?

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External caching could be something like Varnish. It makes it possible to deliver content without using php / Drupal / mysql and is thus very fast. I'm not sure the exact magnitude, but the same server could probably show 50-xxx times more pages per second from Varnish cache than from drupal cache.

So you can delivery a lot of content without using much server power doing it.