Exchange 2007 – High Availability Solution – Cluster Continuous Replication

In my last article : Exchange 2007 - Local Continuous Replication (High Availability) you have seen what LCR is, how it is working and how it is useful in terms of more then have one disk in a Exchange Server. LCR is supported in Exchange 2007 standard edition as well in enterprise edition 2007. And best suitable for small organization.

Cluster Continuous Replication is supported only in Exchange 2007 enterprise edition. It is almost same like Local Continuous Replication however instead of shipping the log file from one disk to another disk, it will ship the log from one server to another server. In earlier version i.e exchange 2003 what we had is active\passive cluster where we will have one shared disk in which the exchange database is stored. By having this CCR technology we are eliminating the shared disk fundamentals what we had in exchange 2003. Responsible for log shipping between the nodes is Microsoft Exchange Replication Service. This is just a basic overview

How this Cluster Continuous Work?
• It will work same as like LCR where we will seed the database and then the log shipping process will take into effect to update the database of passive server storage group from the active server storage group

• One major cause which might come into the picture is, Node A and Node B will communicate with each other via hearbeat. Let say node B is not able to get response from node A due to some network issue but Node A is still alive so it might goof up with the database so here third party referee will  come into the picture . This third party referee is nothing but a QUORUM who will give an update to Node B i.e Majority Node. The way it work is by the mode called as “Majority Node witness”. This Majority Node witness typically hold the role of referee i.e, nothing but you will share one folder which will be created on another server which is not going to be your node A or node B server, it will act as referee. The recommended server where you will set Majority File Share Witness is your Hub Server.

• In CCR also there is potential to data loss. But it won't get loss of much data as compare to LCR, what happen here is we have a transport dumpster which will store the mail comes from hub transport in the hub transport server and then it will pass it to active node. so incase if active node failed to mount then passive node storage group will first check with hub transport server by sending a request to give the information whatever hub server have in the hub transport dumpster and if it is the same data then it will ignore and if it is new then it will write it into the passive server storage group so that is how we have very less chance of loss of data as compare to LCR.

Configuring Cluster Continuous Replication:

In order to have cluster continuous replication
 We need to have AD\DC\GC & DNS server at least in which we have windows 2003 with sp1 or sp2
 One Server with Hub Server Role & CAS Server Role
 Two more member server where we will configure cluster continuous replication with two nic cards.

In my Lab:
 I have one Server called as "MainDC"
 One Server which is having HUB & CAS Role – Server name : HUB-CAS
 Two Member servers with two nic cards – one will be my public card and other will be my private card. Server name : CCR-1 and CCR-2

First thing we need to install a hotfix KB 921181  on both the member servers i.e CCR-1 & CCR-2 because this hotfix will create a share witness file which will have the voter identification for both the node.
Note : The above hotfix need to be installed if you have windows server 2003 with sp1 and not for service pack 2 versiion

First Node Server Ip Configuration (CCR-1):
I have given the network card name as Public & Private
Public NIC :
  Ip address : 192.168.1.4
  Subnet Mask : 255.255.255.0
  DNS : 192.168.1.1
Private Nic :
  Ip address : 10.1.1.1
  Subnet Mask : 255.0.0.0

Second Node Server Configuration (CCR-2) :
I have given the network card name as Public & Private
Public NIC :
  Ip address : 192.168.1.5
  Subnet Mask : 255.255.255.0
  DNS : 192.168.1.1
Private Nic :
  Ip address : 10.1.1.1
  Subnet Mask : 255.0.0.0

                                            Configuring your windows Server 2003 Cluster

Windows 2003 member server will have cluster installed by default and you don’t require installing it, just we need to configure it.
Note: Best practice to configure the cluster is to create a separate account like clusadmin.

Inorder to configure your cluster follow the below steps:
Click on Start => Programs => Administrative Tools => Cluster Administrator and select “create new cluster” under action window and click on OK
Figure1:

Once you click on OK it will open Cluster Configuration Wizard Figure 2:
 

Next it will ask you a cluster name and domain
My domain name: happy.com
Cluster name: VirtualCCR
Figure3:
 

Once you give the unique name it will show you the existing server name as your first node for this cluster
Figure 4:
 

After this it will analyze the configuration
Figure:5

 

Then give one public ip address for accessing this virtual server
Figure 6:
 

Then give the cluster admin account information
Figure 7:
 

Now when you click on next it will show the screen for proposed cluster configuration. This the place where you need to select Majority Node Set instead of Local for enabling File Sharing Witness i.e under propose cluster configuration click on Quorum and then select Majority Node Set
Figure 8:
 

After this it will create cluster for our first node and then click on Finish
Figure 9:
 

Once you click on finish it will open the cluster administrator console
Figure 10:
 

Now I am done with First Node of the cluster as far as cluster configuration is concerned.

Now I need to add CCR-2 (Server) as a part of this node who is going to be my passive node so in order to do that
Right click CCR-1 virtual name as per on the figure 10 and click on NEW and select Node
After selecting the node it will show you welcome screen, just click on NEXT and then it will suggest you to select computer so here you need to browse the second computer who is going to adore the role of passive node for this virtual server. So for me it is going to be CCR-2
Figure 11:
 

Now it will analyze the configuration i.e.,  it will connect to existing cluster node and it will establish connection with active node
Figure 12:
 

Then it will request you to type password who has configured your first node for the virtual cluster environment
Figure 13:
 

Then it will show you the summary of the configuration
Figure 14:
 

Then it will add the node to the cluster
Figure 15:
 

After clicking on Next it will finish the completion of Node configuration
Figure 16:
 

                                                                Configuring Witness File Share

Log on to your Hub Server for configuring witness file share.
 Go to C root Drive and create a folder called as “WitnessFileSharing”
 Right click that folder and go to properties and then click on sharing tab and select sharing option. And then click on Permission and give full control to the user who has created the cluster node.
Figure 17:
 

Note: clusadmin is a sample user with whom i am doing testing. In realtime he would be your cluster administrator.

Now login back to your active server node, currently my active node is CCR-1
Open the command prompt and type the following command
Cluster <ClusterName> res "Majority Node Set" /priv MNSFileShare=<ShareUNCPath>

Cluster VIRTUALCCR res “Majority Node Set” /priv MNSFileShare=\\HUB-CAS\WitnessFileSharing

Note: don’t copy the above command and paste it in command prompt because it will give you an error message suggesting you to type the correct syntax so manually type it.
Figure 18:
 

Now we need to move the cluster group to passive node:so just type the following command
Cluster <ClusterName> group "Cluster Group" /move
i.e cluster virtualccr group “cluster group” /move
Figure 19:
 

Now lets move the cluster group back to CCR-1 by typing this following command – cluster virtualccr group “cluster group” /move

Now lets verify the status:
In order to verify the status type the following command:
Cluster <ClusterName> res "Majority Node Set" /priv
Cluster virtualccr res “Majority Node Set” /priv
Figure 20:
 

In the above figure along with the file it is showing us MNSFileShareCheckInterval and MNSFileShareDelay. This is nothing but it will check the connectivity of active node and default time is 4 minutes.

Already I discussed about Transport Dumpster. Now it’s a time to configure it. First you need to identify what is the maximum size of the message send and received. Microsoft always recommends to increase the size in Transport Dumpster by 1.25 times.

Configuring Transport Dumpster:

First let see the default configuration
 Open the Exchange Management Shell
 Type this command : get-Transportconfig
Figure 21:
 

Now I want the maxDumpster per storage group 30 MB & Dumpster time : 10 days
Set-transportconfig -MaxDumpsterSizePerStorageGroup 30MB -MaxDumpsterTime 10.00:00:00
Now let me check the status i.e get-transportconfig
Figure 22
 

It’s a time to install Exchange 2007 sp1

 Login to active node first.
 Install the prerequisite tools like enable IIS, .net framework, powershell, DTC hotfix and check MMC console version.
 Then run the setup.exe and select install exchange 2007 sp1
 Then click next on introduction page and select I agree in EULA page & click next.
 Error reporting : if it is production server then select Yes or else No
 Under Installation type select the customized one
Figure 23:
 

Under server role selection: select “Active Clustered Mailbox Role”. This will automatically choose management tools and rest of the role will be grayed out.
Figure 24:
 

Under Cluster Setting: Give a Virtual Exchange Server Name and select the mode of clustering as “Continuous Cluster Replication”
Figure 25:
 

Next thing we need to give one virtual public ip address
Figure 26:
 

Once you click on next it will check whether we met the mailbox prerequisite plus cluster mailbox server prerequisite:
Figure 27:
 

Once you click on install, it will install the Cluster mailbox
Figure 28:
 

Now we are done with CCR-1 (Active Node)

Installing Exchange 2007 mailbox server role on Passive Node

Log in to Passive node server
 Install the basic prerequisite like enable IIS, .netframework sp1, powershell and Time zone hotfix.
 Run setup.exe and select install Microsoft exchange server 2007 sp1
 Then follow the instruction till you select customize installation because after clicking on customize installation and then we need to select the option of passive node
Figure 29:
 

Click on next, then it will check for mailbox prerequisite
Figure 30:
 

Then click on install, now it will copy the files, will install the management tool and then mailbox role

Lets see the Exchange virtual server
Figure 31:
 

                                                            Managing Cluster Continuous Replication

When you right click the storage group from the EMC you will get two options for cluster continuous replication:
 Suspend Storage Group Copy
 Restore Storage Group Copy
Figure 32:
 

To halt the replication:
Suspend-StorageGroupCopy -Identity:<Server\StorageGroup> -suspendcomment:<Comment>
Suspend-StorageGroupCopy –Identity:’E2K7CCR\First Storage Group’

To get the status :
Get-StorageGroupCopyStatus -Identity:<StorageGroupName>

"Get storage group copy status" is very good command to know the status of the log shipping and current status
Figure 33:
 

To restart the replication:
Resume-StorageGroupCopy -Identity:<Server\StorageGroup>

How to view the CCR configuration:
Get-MailboxServer -Identity:<CMSName> | Format-List
"Get mailbox  server" will give you the entire information of your Exchange server mailbox.

Get-TransportConfig | Format-List

Collecting Performance Data:

> go to performance wizard (connect it to the passive node of the server)
 Under performance object select MSExchange Replication and choose all instances or choose only the specific storage group
Figure 35
 

How to move a clustered mailbox server between the nodes
Move-ClusteredMailboxServer -Identity:<CMSName> -targetmachine:<PassiveNodeName> -movecomment:<Comment>

How to start the clustered mailbox server
Start-ClusteredMailboxServer -Identity <Name>

How to stop the clustered mailbox server
Stop-ClusteredMailboxServer -Identity <Name> -StopReason:<Comment>

How to move the storage group in a CCR environment
1) Suspend-StorageGroupCopy -Identity:<Server\StorageGroupName>
2) Dismount-database -identity:<Server\StorageGroupName\DatabaseName>
3) Move-StorageGroupPath -Identity:<Server\StorageGroupName> -LogFolderPath:<NewPath> -SystemFolderPath:<NewPath>
4) Resume-StorageGroupCopy -Identity:<Server\StorageGroupName>

How to view the clustered mailbox server status:
Get-ClusteredMailboxServerStatus -Identity:<Name>

How to move the database:
1) Suspend-StorageGroupCopy -Identity:<Server\StorageGroupName>
2) Dismount-Database -Identity:<Server\StorageGroupName\DatabaseName>
3) Move-DatabasePath -Identity:<Server\StorageGroupName\DatabaseName -EdbFilePath:"NewPath"
4) Resume-StorageGroupCopy -Identity:<Server\StorageGroupName>

How to seed the database – update needs to be run on passive node & it should be suspended & all the log file including check point file should be removed
Update-StorageGroupCopy -Identity: <Server\StorageGroupName>
Figure 36
 

Resume-StorageGroupCopy -Identity:<Server\StorageGroupName>

I hope that this article is being very informative for you all. Thank you for spending your time in this matter.

I would like to thanks Henrik from Msexchange.org because for this article I was referencing his article which is published by him for configuring the transport dumpster and also giving permission to publish this article in my blog.

Reference Link:

Cluster Continuous Replication 
Configuring CCR

Related Articles:

Exchange 2007 – High Availability Solution – Local Continuous Replication

Exchange 2007 – High Availability Solution – Cluster Continuous Replication

Exchange 2007 – High Availability Solution – Single Copy Cluster

Exchange 2007 – High Availability Solution – Standby Continuous Replication