Re: how does squid work?

Eric Dahnke wrote:

> How long do the cached images stay cached.

This is determined by three factors:
1. Expiry time set by the origin server (most servers don't).
2. Your refresh_pattern settings in squid.conf
3. Size of your cache

> When they expire (assuming they expire) does squid go get
> the updated copies, or are the cached files simply deleted
> and refreshed upon the next visit.

Unless the expired object has been removed from disk to make space for
other objects, Squid will ask the server if the object has changed using
"If-Modified-Since" requests. In your access log such request will be
logged as TCP_REFRESH_* where * is HIT if object was not modified and
MISS if the object was modified.

--
Henrik Nordstrom
Spare time Squid hacker