Re: [squid-users] How to setup squid proxy to run in fail-over mode

Hi Abdul,

As has been said the most simple solution is to use a PAC file, i'm
using it at my company and balancing the connections depending on the
subnet: subnet A goes throught proxy1 and subnet B goes throught
proxy2. When proxy1 goes down, connections goes to proxy2, but it
doesn´t sinchronyzes the information of the conections, so clients
will have to stablish a new connection to proxy2.You have multiple
examples of configuring a pac file on internet.

Obviouslly this is not the best solution, it is not a load balancing
depending on the amount of "charge" of each proxy. For that you may
need a solution including LinuxVirtualServer (LVS) + Heartbeat (like
ultramonkey), with two virtual/physicall machines acting as load
balancers in Active/Pasive mode (with heartbeat) connected to other
two machines acting as proxys. For the final user it acts as an
individual machine, with only one ip (virtual ip for the hole
structure). It has another advantages, like the LB sinchronyzes the
information of the connections throught UDP multicast, so if one
server goes down, the other proxy have the information of the
connection and the client doesn't have to restart the connection. Also
is a HA solution.

Also is good for stops due to updates, improves, fails, etc on your
servers, its is completely transparent for the users. And you can
increase easily the number of servers acting as proxys.

Hope it can help you.

Gontzal

2009/6/15 K K <kkadow_at_gmail.com>
>
> >>>> 1. Use de WPAD protocol: lets say PROXY squid1; PROXY squid2
> >>>> (this is fail over)
>
> IMHO, using PAC (with or without WPAD) is the simplest and most
> effective approach to failover, requiring no additional software
> beyond a web server to host the PAC file.
>
> With PAC, the browser will automatically switch to the second proxy in
> the list if the first stops responding.  All modern graphical browsers
> support PAC, and nearly all support WPAD.
>
> The PAC script is very powerful, you can use many, but not all,
> Javascript string and numeric functions.  With a little effort you can
> have PAC distribute user load across multiple proxy servers, or even
> hash the request URL so, for example, all requests for dilbert.com
> first go to squid1, to get the most value from cached content.
>
> For more on PAC, see http://wiki.squid-cache.org/Technology/ProxyPac
Received on Tue Jun 16 2009 - 10:58:54 MDT