MPLS WAN

thomasandy32 · ‎04-06-2010

Hello Experts,

Pls find the attached diagram,

I m on a DR site,

Customer requirement is he want his intranet server in HQ (http:a kind of internal Web application) should be failover to DR site whenever the power from the HQ is totally shutdown.this means whenever there is a power outage in HQ , branch office's should continue working with their worflow, they shld access the internal web application through DR site,

AND

Also customer need the replication (mirroring) of the main server to DR site whenever the changes are applicable in the server, He needs the database replication from HQ end to DR side,incase of any failure, the database shld be accessible from DR site,

How can i achieve this.

thanks,

Giuseppe Larosa · ‎04-06-2010

Hello Andy,

how far are the HQ and DR sites?

if they are more then 200 km far away synchronous mirroring is not possible (propagation delay becomes too big) and only asynch mirroring can be used.

You can consider async mirroring like backups: at scheduled time intervals DB is sent to DR (may be incrementally)

You need also to clearly specify with customer how handover to DR web application is done:

that is if it is acceptable for use to reconnect to the web application this could be done with routing only (for example by using the same IP address like an anycast) and having the preferred path to HQ from all sites.

if the customer would expect to go on with the web application on DR web server with no interruption this requires additional activity:

the servers have to be configured as a cluster with a management interface (different from front end where user connects) in order to communicate state information to peer (web sessions and other info)

I would say this makes sense only if sync mirroring is possible otherwise there is no use on switching seamlessy to DR web server with a DB that is not in sync with HQ one.

So I would suggest to better define requirements with customer

Hope to help

Giuseppe

thomasandy32 · ‎04-06-2010

Excellent answer Giuseppe,

1) The HQ site is not more than 200 KM the branch offices are far away, so i shld suggest customer synchronous mirroring

2) that is if it is acceptable for use to reconnect to the web application this could be done with routing only (for example by using the same IP address like an anycast) and having the preferred path to HQ from all sites

I hope what i understand from ur above words is a Anycast routing through MPLS cloud hitting to prefered HQ server. If not then to DR ?? correct me ???????????????? How to configure any document??????

3)the servers have to be configured as a cluster with a management interface (different from front end where user connects) in order to communicate state information to peer (web sessions and other info)

I didnt get ur above 3 statement becz i m unaware how server clustering works?? what i only know is clustering is more than 1 server for backup within a LAN, How this will work when 1server is in HQ and the other is DR any keepalive are there between servers, and suppose if there are then how the ISP edge router PE (which is connecting to HQ) will come to know that i have to route the traffic to DR server.

Still the router configs are not clear for me from my end as well as ISP end,i m wondering how the traffic will be routed to DR.

My Guess:

Ip SLA route tracking by the ISP end and i hope the IP of a server shld be virtual.

Thanks for ur reply,

i was expecting u and u replied thanks once again.

thomasandy32 · ‎04-07-2010

Hello Experts,

Any configuration hints will be highly appreciable,

Thanks,

Leo Laohoo · ‎04-07-2010

You may also want to consider using a WAN Accelerator to improve bandwidth utilization between the primary and DR sites.

thomasandy32 · ‎04-08-2010

Hello,

Can anyone reply to the my mail above and also Can anybody link me to configuration examples ,so the picture may be more clear,

Thanks,