[CentOS] Copy OS live to different hardware

[Les Mikesell]

Bob Puff wrote:
> Hello,
> 
> I've got some CentOS 5.3 servers that I want to clone to a backup server,
> possibly a VM machine.  I want this to be done while the server is up, and
> keep it synced at least once a day.
> 
> I've done this already by using RSYNC, but here's the twist: the backup
> machine could be different hardware, and needs to have a different IP address
> (so they don't conflict).
> 
> My question: exactly what files should I exclude, so that I copy everything
> -except- what pertains to the ethernet card(s), and hard drive mounts.  I know
> of at least:
> 
> /etc/fstab
> /etc/sysconfig/network-scripts/*
> /var/run
> /proc
> 
> But what else?  The original servers may have software raid, so those files
> can't be copied either.

/dev, /sys and /boot - but it is a good idea to use rsync's 
--one-file-system option and explicitly copy the filesystems you want. 
Also, if you are changing files underneath running applications, expect 
some wierd things to happen.  It would be safer to plan to reboot the 
backup if you ever need to activate it - and if you do that you could 
have it running from a different root for the copies.

-- 
   Les Mikesell
    lesmikesell at gmail.com