[CentOS] OT: CentOS server with 2 GbE links to 2 GbE switches

[Scot L. Harris]

On Fri, 2005-08-26 at 09:36, Patrick wrote:
> Hi all,
> 
> I am trying to come up with an architecture that has some redundancy.
> The idea is to hook up the two GbE LAN interfaces of a CentOS server to
> two Gigabit Ethernet switches. In case one switch goes down, there is a
> redundant path (the server is redundant too). Here is the idea:
> 
>                              -----------
>                             |    GbE    |   
>  PCs            ------------|   switch  |------------
>   |            |             -----------             |
>   |   -----------------                        -----------------
>   ---| Workgoup Switch |                      | CentOS/Asterisk |
>   |   -----------------                        -----------------
>   |            |             -----------             |
>  VoIP           ------------|    GbE    |------------
> Phones                      |   switch  |   
>                              -----------
> 
> How would I acomplish this? Can I use IP addresses from one IP network
> (say 10.0.0.0/24) to assign to the 2 LAN ports on the CentOS server and
> a port on each of the GbE switches and then use something like OSPF on
> the switches and the CentOS box to do the routing? Any other ideas?
> 
> Many thanks for your suggestions.

The setup you describe has several single points of failure.  Are the
GbE switches you are using that fragile and likely to fail?



In the network you describe above the workgroup switch and the Asterisk
box are single points of failure.  If you want a redundant system then
you need to eliminate the single points of failure.  You may want to
look at using HSRP or VRRP (HSRP is Cisco specific, VRRP is more
generic) for HA type network solutions.

For the server you will need to look at cluster solutions.

As others have mentioned you can try bonding the interfaces on the
server to provide higher bandwidth but I believe you need to have a
switch that understands bonding as well.

When designing for redundancy and high availability start by identifying
the critical parts of your infrastructure and determine the type of
disasters you want to protect against as well as the likely hood of such
a disaster.  Many things while possible are unlikely or have little or
now impact.  Concentrate on those things that are likely to happen and
have major impact to your systems.

And remember that adding more hardware or making your network more
complex can sometimes increase the likely hood of having a failure cause
service interruptions.

Depending on the costs of taking an outage you may be better off having
a cold spare handy to replace the switch or device that fails.