High Availability squid Proxy

[lingu]

Hi all,

I am running squid integrated with squidguard.dansguardian,clamav
running on single  standalone RHEL 5 server.Also running webmin for
managing squid.This Squid is serving for 4000 clients.

 Since it is serving more users i don't want to take risk by running
single server,if there is any single point of failure will cause all
of my users to standstill.

So i am planned to go for one more  RHEL 5  server with cluster.Can
any one suggest me how to design it either i have to go for common
storage for storing all global files or i need to synchronize both the
server periodically by  running instance on local disk of both the
servers.

Below is  the scenario currently running on the server

squid is under  /etc and squidguard database under /var/lib and
dansguardian config file under /etc/dansguardian and webmin is under
/usr/local

Help me in designing the setup  of high availability squid

Regards,
lingu