Re: [squid-users] Peering squid multiple instances.

[Amos Jeffries]

GIGO . wrote:
Dear Amos,
 
Thank you for your response and better design tips. However i am not able to comprehend it well (due to lack of expereince and knowledge both however at current). So i request you to elaborate it a bit more. Your guidance would be a real valuable.
 
Question 1:
 
You said that under my configuration this is the case:
 
Client -> squidinstance1 -> squidinstance2 -> (web servers)
 
or 
 
client -> squidinstance2 -> webserver
 
Well i am failing to understand how clients can talk to squidinstance2 directly when:
 
1. squidinstance2 is configured with an acl to accept traffic from localhost only.

I did not see any http_access lines in your displayed config. I assumed 
some things wrongly it seems. And also mixed your questions up with 
someone others similar questions.

What you posted was a good setup for failover if a normal caching proxy 
(squid2) dies. Using a non-caching interface instance (squid1) to prefer 
fetching from cache with direct no-caching route as a backup.

In this case the "parent" type was correct and with only two Squid the 
ICP/HTCP/digest selection methods should be avoided.

(The bits I said that lead to your Q2-4 were intended for that other 
setup. Very sorry.)


Question 5:
 
can you please tell some good read for knowledge/concepts builder? I have get hold of squid definitve guide though a very good one however isnt'it a bit outdated.Can you recommend please? Specially on the topics of Authenticating Active directory users in squid proxy.
 

The wiki is where we point people. It started as a copy of the 
definitive guide and the older FAQ guide. Then we tried to improve it, 
increase it and update things for the currently supported Squid releases.

Hopefully its easy enough to read and learn from. Suggestions for 
improvement are always welcome.


----------------------------------------
Date: Wed, 24 Mar 2010 18:06:46 +1300
From: squ...@treenet.co.nz
To: squid-users@squid-cache.org
Subject: Re: [squid-users] Peering squid multiple instances.

GIGO . wrote:
I have successfully setup running of multiple instances of squid for the sake 
of surviving a Cache directory failure. However I still have few confusions 
regarding peering multiple instances of squid. Please guide me in this respect.


In my setup i percept that my second instance is doing caching on behalf of 
requests send to Instance 1? Am i correct.

You are right in your understanding of what you have configured. I've
some suggestions below on a better topology though.


what protocol to select for peers in this scenario? what is the recommendation? 
(carp, digest, or icp/htcp)

Under your current config there is no selection, ALL requests go through
both peers.

Client -> Squid1 -> Squid2 -> WebServer

or

Client -> Squid2 -> WebServer

thus Squid2 and WebServer are both bottleneck points.


If syntax of my cache_peer directive is correct or local loop back address 
should not be used this way?

Syntax is correct.
Use of localhost does not matter. It's a useful choice for providing
some security and extra speed to the inter-proxy traffic.


what is the recommended protocol for peering squids with each other?

Does not matter to your existing config. By reason of the "parent"
selection.


what is the recommended protocl for peering squid with ISA Server.

"parent" is the peering method for origin web servers. With
"originserver" selection method.

Instance 1:

visible_hostname vSquidlhr
unique_hostname vSquidMain
pid_filename /var/run/squid3main.pid
http_port 8080
icp_port 0
snmp_port 3161
access_log /var/logs/access.log
cache_log /var/logs/cache.log

cache_peer 127.0.0.1 parent 3128 0 default no-digest no-query proxy-only 
no-delay
prefer_direct off
cache_dir aufs /var/spool/squid3 100 256 16
coredump_dir /var/spool/squid3
cache deny all



Instance 2:

visible_hostname SquidProxylhr
unique_hostname squidcacheprocess
pid_filename /var/run/squid3cache.pid
http_port 3128
icp_port 0
snmp_port 7172
access_log /var/logs/access2.log
cache_log /var/logs/cache2.log


coredump_dir /cache01/var/spool/squid3
cache_dir aufs /cache01/var/spool/squid3 50000 48 768
cache_swap_low 75
cache_mem 1000 MB
range_offset_limit -1
maximum_object_size 4096 MB
minimum_object_size 12 bytes
quick_abort_min -1


<snip me bad comments>

Amos

--
Please be using
  Current Stable Squid 2.7.STABLE8 or 3.0.STABLE25
  Current Beta Squid 3.1.0.18