April 11th, 2013, 06:38 AM
Load balancing Public A record
I wonder if someone knows of a UK based company that offers public DNS (A record) load balancing? What I mean is a client machine requests the IP address of your A record (www). What is returned to the client is a valid IP address of a working (heatbeat) Ip address. Let's say we have 2 physical web servers serving identicle copies of your web site (www.mydomain.com) but the IP address returned to the requesting client is the IP address of one of these servers that is responding.
I know we have round-robin but that only returns all IP addresses you have set up for your A record without first checking to see if they are up and running and contactable. Not a HA solution in my opinion. What would be really good is if we set a short TTL on the returned IP address that it fails over to the other working web server mid session.
There must be a cost-effective way to do this???
Anyone? Many thanks for looking
April 23rd, 2013, 08:02 AM
There are companies that offer such services, but they tend to be costlier.
Alternatively, what you can do is, have an HA setup. In such a setup there's a floating IP that takes care of the delivery, if one of the the servers go offline, the content gets automatically served from the secondary server. This is a Network load balancing set-up. But unfortunately, it isn't service aware. Meaning, the set-up would understand that the primary server has gone offline, but the data syncing is something that you'd need to carry out manually or by means of rsync.
If you wish to get rid of all this hassle, you can always opt for a Failover Cluster Setup.
April 23rd, 2013, 09:16 AM
Thank you James for your post. We have already in place the Exchange Servers in Hyper-V on a cluster so that's the HA taken care of from an Exchange Server perspective.
My concern is the traffic such as mail flow and client access. We also have Microsoft FOPE (Forefront Online Protection for Exchange) set-up so the mail delivery is also HA. That just leaves the client access for OWA and OMA.
We will be soon setting-up two points of entry to our network at datacentres in Chicago and London. So I am looking for a way of load-balancing externally the dns to point to these entry points but test they are up first before assigning the client an IP address of the A record(s) for OWA and OMA.
If I can achieve this, then everything should be load balanced with the use of DAG for the mail stores in the datacentres.
I still haven't found a company that offers such a service here in the UK. Is it really such an ask that companies will require a load balanced service externally before even hitting our perimitre but testing it is up first. There must be loads of companies requiring this as a service for a whole host of different services.
My apologies for the delayed response. Your requirements can be served, but we'd need to test it ourselves before commenting further on this. In such a set-up it is important to check if it's possible with Exchange in place. Let me get back to you on this in sometime. Can you please PM me your email address?, so that I can get back to you directly if I need any clarification on your requirements.
Last edited by James-A; May 7th, 2013 at 04:59 AM.