LYNC SERVER DISASTER SCENARIOS

Pool Failover Steps 

Imagine 2 Lync pools pool1 and pool2. Both have dedicated SQL BE. SQL1 and SLQ1 

Pool1 is active and hosts the CMS i.e. CMS resides in SQL1. Now we will failover to pool2 

Before performing a pool failover, you need ensure the CMS is always alive else Lync will not work. 

So, while doing a pool failover make sure if the pool which is not going to be active if it holds the CMS 

Get-CsConfigurationStoreLocation 

Then move it to the pool which is going to be active. So, from any FE or the going to be active pool  

NOTE - Moving the CMS is also known as "Failover CMS" run  

Invoke-CsManagementServerFailover -BackupSqlServerFqdn SQL2.UC.com -BackupSqlInstanceName "LYNC" –Force 

Now, Ensure the Edge server Next Hop is pool2 because it was pointing to pool1 which we will failover to pool2 

Set-CsEdgeServer -Identity EdgeServer:edge.uc.com -Registrar Registrar:pool2.uc.com 

 Now you are ready to invoke the pool failover from pool1 to pool2. Run following command to complete the failover. It will ask for confirmation and select yes and finish the steps. 

 Invoke-CsPoolFailover -Pool1.uc.com -DisasterMode 

========================================================================================

Lync 2013 pool failover in details when CMS is down or even if CMS is available 

=========================================== 

  

Lync Server Backup Service provides real-time data replication to keep the pools synchronized. (It replicates 3 set of data USER DATA, CONFERENCE DATA and CMS DATA) 

Get-CsBackupServiceStatus -PoolFQDN          run this for both the pools to see the status of Export and Import 

  

  

If there is a pool pairing between two standard servers SE1 and SE2 

  

SE1 is down. Users of SE1 are facing an outage hence we need to perform a pool failover and for pool failover we need to failover the CMS and CMS was located in SE1 but SE1 is completely down. 

  

Verify location of the CMS  Get-CsConfigurationStoreLocation or Get-CsService –CentralManagement 

  

You will have to failover the CMS before pool failover. Run following command from PowerShell to invoke CMS failover from SE1 to SE2. Make sure that it is completed successfully. Try using the -WhatIf before failing over 

  

Invoke-CsManagementServerFailover -BackupSqlServerFqdn SE2.fabrikam.com – BackupSqlInstanceName “rtc” –Force  (This should always be run from the target pool) 

  

Now run the Get-CsConfigurationStoreLocation to confirm the location of CMS database. 

  

Ensure the replication status of CMS store that it is updated.  Get-CsManagementStoreReplicationStatus –centralmanagementstorestatus 

You must set the edge server next hope to SE2.fabrikam.com because  the Edge pool for SE1 site is still running, and uses the failed pool as a next hop.  

If it does, you must change the Edge pool to use the SE2 pool before failing over the failed Front End pool. Before proceeding to next step. Run following command. Make sure that it is completed successfully. 

  

Set-CsEdgeServer -Identity EdgeServer:edge2.fabrikam.com -Registrar Registrar:SE2.fabrikam.com 

  

OR  

ensure the second SRV pointing to the EDGE server is in public DNS with a different weight to the primary 

OR  

modify SRV pointing to the EDGE of the failed pool to point to the working pool in public DNS 

Now you are ready to invoke the pool failover from SE1 to SE2. Run following command to complete the failover. It will ask for conformation and select yes and finish the steps. 

 Invoke-CsPoolFailover -PoolFQDN SE1.fabrikam.com -DisasterMode 

NOTE    -DisasterMode is used If a pool is no longer accessible. If this parameter is not present that means that the pool is still up and running and that failover occurred by administrator choice; for example, the pool might temporarily be failed over in order to do hardware or software upgrades on the server. 

  

FAILBACK 

  

1. Restore services to failed datacenter and ensure Lync 2013 is functional. 

2. Invoke-CsBackupServiceSync –poolfqdn SE1.fabrikam.com  

3. If required to move CMS back to original pool, this should be done first though it is not required to move the CMS back to the original location. 

4. Invoke-CsPoolfailback –poolfqdn SE1.fabrikam.com –verbose to fail the users back to the original pool 

5. Revert Edge topology changes 

  

Set-CsEdgeServer -Identity EdgeServer:edge1.fabrikam.com -Registrar Registrar:SE1.fabrikam.com