[asterisk-users] How do you harden an Asterisk install?

[shadowym]

I remember reading a small write up somewhere.  I think it was on the
Asterisk Wiki.  I can't find it anymore.  It's probably a bit dated by now
but some of it would still be relevant.

Can anyone recommend a good guide or even some of their own suggestions.  

For clarity, what I mean by hardening is to make an Asterisk Server or
network appliance or embedded server or whatever you want to call it, as
fail safe, stable, and reliable as possible.  Just like an expensive
traditional PBX.  This is for a small business application of 50 extensions
or less.  It can't be too crazy like redundant servers or anything like
that.  I am looking for ideas like RAID 1, redundant power supply, cron job
to reboot every night (yuck!), disable caching(?), Astlinux on embedded with
CF, yada yada!

Anyway to set up automatic failover to a second Network Card with same IP if
primary network card fails?  That is one point of failure I haven't found a
way around yet.  Failure of the managed switch is another one I get a bit
paranoid about.  Switches generally don't fail but I'd like to have some
sort of fail safe plan.