by Shijaz Abdulla
on 14.05.2009 at 16:06
For those of you still upgrading to Exchange Server 2007 or consolidating your Exchange Servers, and are considering some of the High Availability solutions, I have a clear recommendation:
Avoid Single Copy Cluster (SCC); Use CCR (Cluster Continuous Replication) or SCR (Standby Continuous Replication) instead!
- SCC is not a complete HA solution. There exists a single point of failure – the shared storage! In CCR or SCR, there are two replicas of the same data.
- You don’t need a shared storage for CCR or SCR
- You don’t need third-party replication software (such as Double-Take) to span the database over two data centers.
- Improved failover behavior when compared to SCC.
- Installation is easier than SCC, and you do not need to perform additional hardware validation because shared storage is not required.
- Easier to manage.
- Improve backup performance, by letting backups to run from the passive copy of the data
- Single Copy Cluster (SCC) is being discontinued in Exchange Server 2010
So, for all future Exchange 2007 HA designs, please keep this in mind!
Fig 1. (below) Single Copy Cluster
Fig 2. (below) Cluster Continuous Replication
by Shijaz Abdulla
on 03.05.2009 at 17:29
This article gives step-by-step explanation on how to implement Single Copy Cluster in Microsoft Exchange Server 2007.
For Exchange Server 2003 administrators:
Short and sweet: A two-node Single Copy Cluster in Exchange Server 2007 works just about the same way a two-node Active-Passive cluster works in Exchange Server 2003.
For newbie Exchange administrators:
It is assumed you know what the following terms mean:
A two-node single copy cluster (SCC) is a clustered mailbox server that uses shared storage in a failover cluster configuration to allow multiple servers to manage a single copy of the storage groups. In short, the Exchange data is stored on a shared storage device (such as a Storage Area Network – SAN) and is connected to two server computers, but can be accessed by only one at a time. The server computer that has access to the storage resource at any given point of time is called the Active node and the server computer is not active is called the Passive node. When the active node fails, the passive node gains access to the shared storage and the Exchange services run on the second node. The passive node then becomes active and this process is called failover.
Task 1 of : Configure Network Cards
Configure two network cards in each node: a public network card for the clients and a private network card for the two server nodes.
To configure a cluster, you need a minimum of two network cards on each node. Verify that you have at least two on each of your two servers.
To easily identify the network cards, rename one card to "Public" and the other to "Private". The Public NIC on each server connects to your LAN and will have an IP address on your local LAN. The Private NIC on your server connects to private network shared between your two nodes. This can be a cross-cable connection directly drawn between the Private NIC of Node1 and the Private NIC of Node2. Use an IP address scheme that is different from your LAN IP range for the Private interfaces. The Private interface is used for "heartbeat" communication between the nodes (to see if the other node is "alive").
Task 2 of : Configure Shared Storage
Configure shared data storage, and assign the same drive letter for the shared disk storage on both nodes in the SCC cluster
Configure your shared storage device and create volumes for use by the Exchange cluster. For information on how to do this, refer hardware documentation/vendor.
Once the volumes have been created, map them on both servers by the same drive letter using Disk Management. (Right-click My Computer > Manage > Disk Management)
Task 3 of : Create Windows Cluster User Account
Create a Windows cluster service account that will be used by the clustering service to start and stop service during failover. The necessary permissions for this account are granted when configuring the cluster.
Open Active Directory Users & Computers
Create a user (say) CLUSTERADMIN.
Set Password Never Expires for this user. You don’t want the password time bomb to blow on your face!
Task 4 of : Create the Cluster
Create a new cluster on the first node by using the graphical Cluster Administrator tool or the cluster.exe command-line tool.
See my article "How to setup an Exchange 2003 cluster" and follow only step 1 and step 2 to create the cluster.
Add the second node to the cluster, by specifying the computer name and the password for the cluster service account. If you wanted to create a multi-node cluster, add all the nodes in this step.
Task 4 of : Install Mailbox Server Role
Install the Exchange Server 2007 Mailbox Role on the active node
Start Exchange Server 2007 setup and choose Custom Exchange Server Installation. Select the Active Clustered Mailbox Role.
During installation, you will be prompted for the clustered Virtual Name and the clustered Virtual IP. This is the "virtual" hostname/IP that will always be online regardless of which node is up. The virtual hostname and virtual IP address is created as a resource on the cluster. Clients will be configured to use this virtual hostname.
Note: You can also run setup from the command prompt with the following options: /newcms /CMSname:ClusterMailboxServerName /CMSIPAddress:ClusteredMailboxServerNameIPAddress /CMSSharedStorage CMSDataPath
If applicable, move existing storage groups and mailbox databases to the active node by using the Move-StorageGroupPath and Move-DatabasePath cmdlets in the Exchange Management Shell. Brief syntax is as follows:
Move-StorageGroupPath -Identity <StorageGroupIdParameter> [-ConfigurationOnly <SwitchParameter>] [-CopyLogFolderPath <NonRootLocalLongFullPath>] [-CopySystemFolderPath <NonRootLocalLongFullPath>] [-DomainController <Fqdn>] [-Force <SwitchParameter>] [-LogFolderPath <NonRootLocalLongFullPath>] [-SystemFolderPath <NonRootLocalLongFullPath>]
Move-DatabasePath -Identity <DatabaseIdParameter> [-ConfigurationOnly <SwitchParameter>] [-CopyEdbFilePath <EdbFilePath>] [-DomainController <Fqdn>] [-EdbFilePath <EdbFilePath>] [-Force <SwitchParameter>]
Your first node is now ready. Install the Mailbox Server role on the passive node. Select Custom Exchange Server Installation, choose the Passive Clustered Mailbox Role option. Once setup completes, you will be able to failover from the active node to the passive node. Test the failover using Move-ClusteredMailboxServer Cmdlet.
Important: Always test the failover (also called ‘Handoff’) using the Move-ClusteredMailboxServer cmdlet on Exchange Server 2007. It is recommended NOT to
use the Move Group option in Cluster Administrator.
Move mailboxes or create new mailboxes on the active node.