[squid-users] Multisite ICP peering

From: Chris Toft <ctoft_at_fairfaxdigital.com.au>
Date: Fri, 29 Oct 2010 17:02:10 +1100

Hi,

I am having an issue with getting multisite ICP peering to work correctly.

Let me lay out the scenario.

Two sites, one primary and one DR.

3 squid caches on the primary site, 2 on the secondary site in front of a cluster of 4 back end web servers on each site.

Primary Site
I have set them up so when requests hit the squid caches (behind a loadbalancer) on each site they will check their squid peers for the image before passing to the back end. This is exactly what we wanted.

Secondary Site
Again setup the same as the primary site but in the configs all 5 squid caches are listed as multicast peers, but when the secondary site is hit it only checks the caches on that site and then goes to the origin webservers.

The idea being the primary site will get hit 90% of the time and therefore have a "hot" cache, with 10% of traffic hitting the secondary site to give a "warm" cache. This being the case we wanted the secondary site squid caches to use the multicast peers in the primary site before hitting the backend webservers.

I have tried various options of multicast, sibling, parent for the type of server.
I have tried using weighting to make the primary site caches a higher priority than the backend web servers
There are no connectivity issues because if I comment out the secondary site webservers in the configs then it will try the primary site squid caches and then fall back to the primary site webservers.

How can I setup the config so that when a request comes in to the secondary site it will check the primary site cache for an object before falling back to the webservers???

Cache_peer section of my config is shown below.

The xx.xx.22.xx subnet is my secondary site

# Webservers (on secondary site)
cache_peer xx.xx.22.166 parent 80 0 no-query originserver round-robin monitorurl=http://ourdomain.com/img/noPhoto.gif monitortimeout=10 connect-timeout=5 monitorinterval=5 no-digest

cache_peer xx.xx.22.167 parent 80 0 no-query originserver round-robin monitorurl=http://ourdomain.com/img/noPhoto.gif monitortimeout=10 connect-timeout=5 monitorinterval=5 no-digest

cache_peer xx.xx.22.168 parent 80 0 no-query originserver round-robin monitorurl=http://ourdomain.com/img/noPhoto.gif monitortimeout=10 connect-timeout=5 monitorinterval=5 no-digest

cache_peer xx.xx.22.169 parent 80 0 no-query originserver round-robin monitorurl=http://ourdomain.com/img/noPhoto.gif monitortimeout=10 connect-timeout=5 monitorinterval=5 no-digest

# Squid siblings (secondary site)
cache_peer xx.xx.22.152 multicast 80 3130 connect-timeout=5 multicast-responder multicast-siblings
cache_peer xx.xx.22.153 multicast 80 3130 connect-timeout=5 multicast-responder multicast-siblings
# Squd siblings (primary site)
cache_peer xx.xx.26.238 multicast 80 3130 connect-timeout=5 multicast-responder multicast-siblings
cache_peer xx.xx.26.188 multicast 80 3130 connect-timeout=5 multicast-responder multicast-siblings
cache_peer xx.xx.26.205 multicast 80 3130 connect-timeout=5 multicast-responder multicast-siblings

# Multicast ICP peers
cache_peer xxx.128.0.112 multicast 80 3130 ttl=16

Thanks in advance for any assistance you can give.

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Received on Fri Oct 29 2010 - 06:02:22 MDT

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