Since Exchange 2010 CAS servers now handle all internal and external client traffic to Exchange mailbox servers including Outlook MAPI traffic, the need for a highly available CAS array is critical to your design.
So how do you load balance MAPI traffic? I found a some useful bits of information to help out:
New-ClientAccessArray –Name “School CAS Array” –Fqdn “outlook.school.edu” –Site “Boulder”
5. You need to revisit any Exchange databases that were created before the CAS array was created and set the rpcclientaccessserver property to match the newly created CAS array. Such as:
Set-MailboxDatabase DB1 -RpcClientAccessServer “outlook.school.edu”
For more on Exchange Server 2010 CAS visit here.
Do you know if it is supported to use the DAG IP address for the CAA? In a 2 node DAG, seems a sensible way to achieve automatic failover?
I wouldn't recommend using the same IP for CAS Array and DAG. Two different failover and availability solutions.
If we have CAS Servers on different data centers across sites and we will be planning to use a 3rd party NLB. Do we still need to create the CAS Array using the command New-ClientAccessArray?
Sorry I might need to rephrase my question. I will give you my setup
PRODUCTIONDC - This is a Production DC
PRODUCTIONEXC - This is a Production Exchange Server running all roles. HT/CAS/MB
CAS Configuration for PRODUCTIONEXC
External URL: http://webmail.domain.com
Internal URL: http://PRODUCTIONEXC
DRDC - This is a DR DC
DREXC - This is a DR Exchange Server running all roles. HT/CAS/MB
CAS Configuration for DREXC
Internal URL: http://DREXC
Both have DAG configured, because if I stop the Information Store on PRODUCTIONEXC, the database will failover to DREXC and this is working correctly.
I am using a 3rd party virtual appliance NLB. I have configured both PRODEXC and DREXC as part of the pool. Do I still need to configure the CAS Array if I have created a pool in my NLB?
Currently all my Outlook users are connecting to PRODUCTIONEXC.
My question is when PRODUCTIONEXC is down, how do I load balance the CAS Array across sites based on my setup?
Do I still need to reconfigure the Outlook (as it is currently pointing to PRODUCTIONEXC) for it to get it working?
See this Exchange 2010 site failover article under 'activating CAS roles': technet.microsoft.com/.../dd351049.aspx
It will more likely involve manual DNS changes to make it work with different subnets/sites.
Can you please advise on the following setup?
We have two datacenters with different subnets but both are in a single AD site as they are conencted by a high speed link. One is for production and one is for recovery, but we plan to use the same external url for both.
We are looking to implement a single CAS array with a CAS server in each location being a member of the array.
A DAG group with a node in each location will be used for mailboxes.
Each location will also have an edge server for mail routing.
My question is,
Can we use the CASArray to provide redundancy for the external accesses such as OWA and Outlook Anywhere. So if the CAS server in the array in the prod location failed, would external users be directed to the CAS in the DR site for remote access as it is all in one site?
If the secondary site is passive, please read this failover article under 'activating CAS roles': technet.microsoft.com/.../dd351049.aspx
It will more likely involve manual DNS change during a site failover.
Do we need to perform Set-MailboxDatabase for Exchange 2003 databases if we wish to use ClientAccessArray for Exchange 2003 databases?
I have six virtual machines in which I have configured AD and DNS on one machine and CAS1 (Exchange 2010) , CAS2, Mailbox1 (for CAS1), Mailbox2 (for CAS2) and CASARRAY on another machines. And they all are in the same domain. I add NLB features on CAS1, CAS2 and CASARRAY. I have added CAS1 and CAS2 in the nlb and gave ip address of CASARRAY as cluster IP. The status for CAS1 and CAS2 is showing "converged" in NLB. I have run command for creating new cas array and assigned mailbox to this cas array. But I am unable to open "OWA" page from cluster ip. Either it is opened by ip address of CAS1 or CAS2 but not through cluster's ip.
So kindly give some comments about above to resolve the issue.
Thanks and Regards,
i have two servers each one have all the rules hub mb cas ... is it recommended to run cas array and DAG between them ?
i saw microsoft article not recommend these kind of setup due to the HW conflict between failover and nlb
what is ur opinion ?
This is ggood article but i am confused with CAS array and its load balancing stuff.
You have mentioned that "Load balance your CAS servers in a CAS array" now this statement is opposite to the one mentioned in to below technet
in this post, brian has mentioned that CASarray doesn't load balance your traffic. CASArray is an Active Directory object used to automate some functions within Exchange and that's all. it never load balance OWA,OA,MAPI,OAB,andd other web seervices.
Could you please let me know whether Cas array load balance traffic or not
@ Raxit -
The CAS Array is indeed an AD object however you still need to load balance your pool of CAS servers with the steps in posted in the blog post.
Nice job. Mark, best regards.
I met you in SFC, IPTV team.
Can I use the WLB with a Non-DAG Exchange 2010 setup as I understand WLB is not supported in a DAG configuration.