Two node DAG maintenance during the power shutdown activity or electrical maintenance

Two node DAG maintenance during the power shutdown activity or electrical maintenance

We have to put the DAG member servers in maintenance mode during the datacenter maintenance or during the power shutdown activities or installing exchange updates/roll ups. Not necessary to put DAG members in maintenance mode for windows updates because windows updates is for operating system and not for exchange right, however if you feel you want put maintenance mode even in windows updates you can.

To bring the DAG member to the maintenance mode need not follow manual steps but certain planning is essentially required, let me explain you how to carry this activity

Assume that we have DAG configured in two node, now execute the below inbuilt script, you may have question what this command will do. This command makes few changes such as moves all the active database copies to the another DAG member, pause the cluster services and blocks the auto activation,

Now DAG member safe with passive mailbox database copies, this script basically stops all the communication with other DAG member server

During the execution as shown below you observe warning just be patience and ignore

.\StartDagServerMaintenance.ps1 –server ex2010a

After completing the above command check the database status by executing the below command

You can observe whichever the mailbox database moved ‘last inspected logs time stamp’

Now you can safely shutdown the DAG member (the server on which you executed the above script)

Once maintenance activity completed execute the below mentioned script to stop the maintenance

This will makes the server back to DAG communication after that you have to distribute the mailbox databases for that execute the below command

.\RedistributeActiveDatabases.ps1 –DagName DAG01 –BalanceDBsByActivationPreference –Confirm:$false   

Mailboxdatabases distributed across the two DAG members by referring the activation preference number

Brief summary

Shutdown servers in sequence

1. Mailbox server 01 which doesn’t hold any active database copies

2. Dismount the mailbox databases on server02 and shutdown

3. Shutdown the file share witness server (if you shutdown file share witness in before mailbox server then might endup with some issues because DAG will lose the quorum. If you made FS down but mailbox servers still ON then start FS wait for few minutes then shutdown mailbox server and then finally file share witness)

3. then shutdown HT,CAS and EDGE

Switching on the servers in sequence

1.Start File share witness server

2.start server02 and mount the databases

3.start HT CAS Edge servers

4.Observe mail flow by sending couple of mails and once everything settled distribute the mailboxdatabases as explained in earlier steps

Everything is possible keep learning J

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