Re: [squid-users] Some queries about cache_peer

Bijayant Kumar

--- On Thu, 31/7/08, Amos Jeffries <squid3_at_treenet.co.nz> wrote:

> From: Amos Jeffries <squid3_at_treenet.co.nz>
> Subject: Re: [squid-users] Some queries about cache_peer
> To: bijayant4u_at_yahoo.com
> Cc: "squid users" <squid-users_at_squid-cache.org>
> Date: Thursday, 31 July, 2008, 5:09 PM
> bijayant kumar wrote:
> >> From: Amos Jeffries <squid3_at_treenet.co.nz>
> >> Subject: Re: [squid-users] Some queries about
> cache_peer
> >> To: bijayant4u_at_yahoo.com
> >> Cc: "squid users"
> <squid-users_at_squid-cache.org>
> >> Date: Thursday, 31 July, 2008, 9:31 AM
> >>> Hello list,
> >>>
> >>> I tried to set up cache_peer, but i could not
> >> understand that it has setup
> >>> or not. Please give some inputs.
> >>>
> >>> Scenario:-
> >>>
> >>> I have setup three proxy-servers.squid 3.0.7
> Stable
> >>> proxy1 192.168.99.134
> >>> proxy2 192.168.99.135
> >>> proxy3 192.168.99.121
> >>>
> >>> Lan Computer 192.168.99.23.
> >>>
> >>> On my Lan Computer, i have configured proxy in
> my
> >> browser as
> >>> 192.168.99.134 ie proxy1. All request first go
> to
> >> proxy1.
> >>> In Proxy1 squid.conf:-
> >>> cache_peer 192.168.99.135 parent 3128
> 3130
> >> proxy-only default
> >>> cache_peer 192.168.99.121 parent 3128
> 3130
> >> proxy-only
> >>> cache_peer_domain 192.168.99.135 .com
> >>> cache_peer_domain 192.168.99.121 .net
> >>>
> >>> In proxy2 and proxy3 no cache_peer is
> configured.
> >>>
> >>> I can browse the web. But i didnt understand
> the
> >> working. I have some
> >>> queries regarding this scenario:
> >>> If the page is not in any of the proxy server,
> then
> >> which proxy server
> >>> will go to internet and fetch for the user. I
> mean if
> >> user access any
> >>> ".net" domain then the request will
> come to
> >> the proxy1 first, it will
> >>> query to the proxy3, if its there it will be
> delivered
> >> else the page will
> >>> be fetched from the internet ,Same is for the
> >> ".com" domain right?
> >>
> >> Usually. If netdb/icmp has been enabled squid will
> keep
> >> records of
> >> response times and go to whichever of peer/web
> responds
> >> fastest. thinking
> >> fastest available service is usually best to use.
> >>
> >> Check your access.log for info on which is being
> selected
> >> for each request.
> >>
> >>> Then my question is,
> >>> 1) which server will query to the internet for
> the
> >> page which is not in
> >>> the cache ie ".net" dedicated server
> or the
> >> main proxy1 server?
> >>
> >> Under only cache_peer_domain, maybe both. Use
> >> 'never_direct' to force
> >> requests to go via peers.
> >>
> > If i use 'never_direct' option then if parent
> cache servers will go down then no body will be able to
> browse the web. And if i will not use 'never_direct'
> option then fetching of object will be done by proxy1,if
> object not found in any cache(proxy2/proxy3), am i right?
>
> Yes.

>
> >
> >>> 2) The new page will be written to the which
> cache,
> >> proxy1 or
> >>> proxy2/proxy3
> >> 'proxy-only' prevents caching at proxy1 if
> request
> >> came from peer. If
> >> request came from web DIRECT then it can be cached
> at
> >> proxy1 and used
> >> later.
> > In my configuration, proxy1 will query to the internet
> for new objects and hence the cache will be populated of
> proxy1 only, no matter it is of ".net" domain or
> of ".com" domain. Then the new entry of
> ".net" and ".com" domain will never be
> written to the cache of the dedicated caching server for the
> same.
> > If i am right in my analogy then can you please
> suggest me to how to avoid this situation. I mean that
> ".net" cache will be written to ".net"
> dedicated server(proxy3) and ".com" cache will be
> written to the proxy2.
>
> In squid you only have a choice of peers vs DIRECT.
>
> Your config earlier was workable, in which case squid will
> make that
> choice every request. Usually going peers, but sometimes
> going DIRECT.
>
> Or you can force a choice yourself with never_direct
> (opposite is
> always_direct, but its clear to me you don't want
> that).
>
> It's up to you.
>
> To decide if a cache of 100% .com traffic is worth the
> small risk of no
> access to .com at all when proxy2 goes down. Which is only
> 2x the same
> risk of proxy1 going down by itself anyway.
>
> Keeping in mind that a quick admin reconfigure of proxy1
> (commenting out
> the proxy2 lines) can restore access while proxy2 is
> debugged about why
> it went down.
>
It means that this configuration will not serve my purpose of using cache_peer. I also can not afford of any down time also.
I wanted to use proxy servers in my network which are 2 to 3 in numbers, share their cache among them. To achieve this setting shall i use DNS round robin or squid round robin along with the cache_peer settings in all the three server's squid.conf ? Can you give me some input to achieve this, it would be great help.

Thanks & Regards
Bijayant
 
> Amos
> --
> Please use Squid 2.7.STABLE3 or 3.0.STABLE8 Send instant messages to your online friends http://uk.messenger.yahoo.com
Received on Thu Jul 31 2008 - 12:01:13 MDT