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High Availability - exchange 2010 - CAS

Hi,

I have two exchange 2010 servers with all in one role (CAS/HUB/MBX). I configured DAG and database having copy in second server. All users are connecting to exchange using first server name exch01.domain.local in their outlook. But if the exch01 server goes down, outlook still try to connect exch01 only, all databases are mounted in exch02 server and if we access https://exch02/owa we are able to access the mails through web. But outlook does not change the connection to exch02. What we can do in this scenario.

Is Cas array can be implemented in this scenario? because I don't have any load balancing configured for CAS server as it is part of all in one server

Thnaks

la-tempestad

Because outlook is only look at the exchange server value at the e-mail account properties,I don't think you can dynamically change the server by just switching off the exch01.

Maybe you would be able to use some GPO to implement the changes for all the domain users unless you are not using any cluster array for CAS.

Regards
la

Amit

This is due to your DB's are pointing to CAS server which is also down. You need to setup CAS Array along with Hardware load balancer to overcome this issue.

kolathaya123

ASKER

Hardware load balance is not possible as both exchange server are having all roles. Can we implement casArray for my existing setup.

Amit

I don't see any benefit of CAS array without HLB. Read this
http://blogs.technet.com/b/exchange/archive/2012/03/23/demystifying-the-cas-array-object-part-1.aspx

kolathaya123

ASKER

Or is it possible to change the CAS server into exch02 by giving some commands manually? So, users can connect to exch02 server when they open outlook

Amit

Ya that you can do using powershell command. You need to pipe -RpcClientAccessServer
http://exchangeserverpro.com/exchange-server-2010-cas-array/

kolathaya123

ASKER

Yes i did alreday thanks

Simon Butler (Sembee)

I have to disagree with the post on a CAS Array having no value without a load balancer. Every implementation of Exchange 2010 I do gets a CAS Array. While you don't get automatic failover, you can change the DNS record to get the clients to switch over to the other server.

Therefore you need an RPC CAS array configured. The host name used must NOT resolve on the internet, be used for anything else and does not need to be on the SSL certificate.

Autodiscover will not redirect the clients because even though the server is down, it is still valid.

Simon.

kolathaya123

ASKER

Hi Sembee2,

Means Even if I not configured NLB between two CAS server, I can create a cas array called cas.domain.local and point the IP into CAS01 or CAS02 right? If cas01 is down I can point and cas.domain.local ip into cas02 server IP and it should work right.

thanks

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Simon Butler (Sembee)

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Amit

Guys, no offense, but i still don't see any value of CAS array with HLB. It is waste of time according to me. what HA are we getting here, if we are changing DNS record for failover. CAS array doesn't give any HA. Not sure, if your business can compromise with a downtime.

I have client who can't afford few minutes of downtime. Rest you can decide. If that fits to your requirement.

Simon Butler (Sembee)

Do you mean CAS Array without a HLB?
Why not deploy one? It takes three minutes to setup and if the implementation changes later on then you don't have to visit every machine to update them - particularly considering there is NO automatic way of updating the clients without manual intervention.

I put a CAS Array in place on every deployment I do, no matter what the size.

It also comes in handy if you decide to migrate to a new server, for the same reason as above.

Simon.

kolathaya123

ASKER

dear amit..

the client can afford small downtime...

Thanks