Design question for Disaster Recovery

nadeemr · ‎02-01-2006

Hi,

One of my customer needs a Disaster Recovery Solution for following scenario:

- Primary Data Center is at SITE A, and the Backup Data Center is at SITE B.

- Clients are located at multiple other branch offices.

- Interconnectivity b/w all sites is on MPLS VPN. All sites have point-to-point connection to MPLS cloud.

- SITE A connects to MPLS cloud using dual 7206VXR routers. Each 7206 has dual E3 links. SITE B also has similary scenario.

- Branch Offices connect to MPLS cloud using single 2800 router. Each 2800 has single E1 link.

- Traffic is IP only.

The customer wants to do this:

1. If SITE A is up and SERVER A is down, the client to server traffic should be redirected towards SERVER B at SITE B. When Server A becomes available again, traffic should be redirected back to Server A.

2. If SITE A is down (obviously SERVER A will also become unavailable) the traffic should again be redirected towards SERVER B at SITE B. When SITE A becomes available again, traffic should be redirected back to Server A.

Can anyone help?

regards,

Gilles Dufour · ‎02-02-2006

for point 2/, since site A is down, site A can't redirect the client to site B.

Therefore, the redirect must come from a separate device.

I would suggest a GSS [global site selector].

The CSS will monitor site A and site B and responds to dns request to forward client to either A or B.

For point 1/, you will need a CSS to perform the monitoring of the servers and to redirect client to the other side.

This is easily done with the primarysorryserver function.

In conclusion, you would need a GSS placed in a central location and 1 [or 2] CSS for each location.

Regards,

Gilles.

nadeemr · ‎02-02-2006

Hi Gilles,

Actually the customer wants to do achieve his target with minimum investment. I already gave him a solution based on GSS and CSS, but he is not willing to go for it due to cost.

What I have in mind is to utilize IOS SLB feature in 7200's. I will advertise a single Virtual Server IP from SITE A and SITE B, with SITE A having a smaller metric. Theoritically, I believe it should work. What do you think?

regards,

Gilles Dufour · ‎02-03-2006

yes, it should work like this.

Good idea.

Gilles.