Poor Mans CAS load balancing solutions

Status
Not open for further replies.
A

AGSS



I am looking to load balance 2 CAS servers without NLB and hardware load balancer because we have the 2 cas server configured with Mailboxes and DAGs.

External load balancing will be done with TMG.

From what I have read internally you can configure round robin DNS for cas where the CAS array would have 2 dns records internally and you would set the TTL to 5 minutes lets say. Is that a viable solutions? Would there be any manual intervention after the 5 minutes? If one CAS server is offline would the client go to the other after 5 minutes?
 
M

Mike Pfeiffer

The thing about round robin is that it's only good for load balancing if both servers are online. If one server goes down, the dns server will continue to return both IP addresses to clients. So for HA, no, round robin dns is not a viable solution.
 
C

Casper Pieterse



Do you realy need to NLB or do you just want to create a highly availble solution?

Casper Pieterse, Principle Consultant - UC, Dimension Data South Africa, Microsoft Certified Master: Exchange 2007
 
J

Jon-Alfred Smith



I am looking to load balance 2 CAS servers without NLB and hardware load balancer because we have the 2 cas server configured with Mailboxes and DAGs. External load balancing will be done with TMG.

The only sensible solution in this scenario is to use a low-cost hardware load balancer. Take a look at these two articles by Henrik Walther:

Uncovering the new RPC Client Access Service in Exchange 2010 (Part 4)
http://www.msexchange.org/articles_tutorials/exchange-server-2007/planning-architecture/uncovering-new-rpc-client-access-service-exchange-2010-part4.html

Load Balancing Exchange 2010 Client Access Servers using an Hardware Load Balancer Solution (Part 1)
http://www.msexchange.org/articles_tutorials/exchange-server-2010/high-availability-recovery/load-balancing-exchange-2010-client-access-servers-using-hardware-load-balancer-solution-part1.html

We have just implemented it in a similar environment. The Virtual LoadMaster runs on every VMware platform (even Fusion).
http://www.kemptechnologies.com/emea/server-load-balancing-appliances/virtual-loadbalancer/vlm-overview.html

MCTS: Messaging | MCSE: S+M | Small Business Specialist
 
R

ricdgr

If you have spare hardware or are running a virtualization technology that supports free linux distributions, you can use keepalived + LVS. The only cost will be the time you take to setup it. Works great on my setup.
 
J

jader3rd

Do you have an IIS server? You can use that for load balancing.
 
A

AGSS

Can you provide more information on the technology you are referring to? Is there a cost?
 
C

chrislehr

check out Kemp for relatively affordable load balancers for exchange. Also, HT can be load balanced by two NAT entries and MX records, and CAS is a relatively easy manual failover as long as you plan certificates properly.
 
Status
Not open for further replies.
Top