Mailing List Archive

Kamil Radziszewski wrote:
> How can i replace the squid command "cache_peer" in varnish ??

No. There is no cache peering in Varnish - and most likely there won't
be. In most cases more or less just as fast to fetch the content from
the backend. ICP in Squid is first and foremost designed for use in
forward proxies behind a slow internet connection.


Per.

On Wed, 25 Jul 2007, Per Andreas Buer wrote:
> Kamil Radziszewski wrote:
>> How can i replace the squid command "cache_peer" in varnish ??
>
> No. There is no cache peering in Varnish - and most likely there won't
> be. In most cases more or less just as fast to fetch the content from
> the backend.

Why, do you have any data which indicates that fetching content from the
backend is as fast as fetching it from a peer? Some backends can take
several seconds to respond, if they are under heavy load and have to hit
a database. Fetching data from a cache peer shouldn't take many
milliseconds. Of course this could vary from system to system...

> ICP in Squid is first and foremost designed for use in
> forward proxies behind a slow internet connection.

What about the hypertext caching protocol, which was designed to replace
ICP?

- Andreas

In message <20070725205709.J75759 at verden.pvv.ntnu.no>, =?ISO-8859-1?Q?Andreas_R
=F8sdal?= writes:
>On Wed, 25 Jul 2007, Per Andreas Buer wrote:
>> Kamil Radziszewski wrote:
>>> How can i replace the squid command "cache_peer" in varnish ??
>>
>> No. There is no cache peering in Varnish - and most likely there won't
>> be. In most cases more or less just as fast to fetch the content from
>> the backend.
>
>Why, do you have any data which indicates that fetching content from the
>backend is as fast as fetching it from a peer? Some backends can take
>several seconds to respond, if they are under heavy load and have to hit
>a database. Fetching data from a cache peer shouldn't take many
>milliseconds. Of course this could vary from system to system...

Absent any evidence to the contrary, our current thinking is that
it is a better idea to have a two-layer varnish setup than a peer
to peer protocol.

--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.