Re: [squid-users] Re: cache_dir size v.s. available RAM

On 25/08/2013 11:20 a.m., HillTopsGM wrote:
> In connection with my last post, I also had this question:
>
> Let's say that with my 4GB of RAM I decided to create a total cache storage
> area that was 650GB; obviously the index would be much larger than could be
> stored in RAM.
>
> If my primary purpose was to 'archive' my windows updates, I'd expect that
> it would take the system only a couple of seconds to review the index that
> would spill over to the drive, and then we'd be back in business for the
> updates - no?

Sort of. This "couple of seconds delay" would happen on *every* HTTP
request to the proxy.

> I simply want the Proxy to help serve updates of all programs - Windows,
> Browser updates like Firefox, Thunderbird, Adobe Reader, Skype, nVidia
> Driver updates (100's of MB at a crack), etc, etc.
>
> I was thinking of creating a rule (maybe someone could help be write it so
> it makes sense) that all sites would be accessed directly and told NOT TO BE
> cached.

You seem to have the common misunderstanding about what DIRECT is. HTTP
permits an arbitrarily long chaining of proxies:

     client->A->B->C->D->E->F->..... -> origin server

always_direct causes Squid to ignore any cache_peer which you have
configured and use DNS lookup to fetch the object DIRECT-ly from the
origin. Giving an error if the DNS produces no results or is not working.

never_direct does the opposite and forces Squid to ignore DNS for the
domain being requested and just send to cache_peer. Giving an error if
the cache_peer are unavailable.

So:
* Squid always services the request recieved.

* "cache deny xxx" prevents the reponse matching xxx being stored is all.

* "refresh_pattern" operates on already stored content in determining
whether it can be a HIT or needs REFRESH-ing.

Amos
Received on Sun Aug 25 2013 - 01:59:51 MDT