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Wednesday, April 19, 2017

Accelerating Exchange 2016 DAG (Database Availability Group) replication with Riverbed SteelHead

I’ve recently had to work with a Riverbed engineer to determine why the traffic between an Exchange server in Bermuda and London was not being accelerated by the Riverbeds between the two sites.  The following Riverbed  configuration guide was what I used in the past for Exchange 2010 environments:

Optimizing Database Availability Group (DAG) Replication for Microsoft Exchange 2010 (Testing Guide)
https://splash.riverbed.com/docs/DOC-1280

Since the the configuration guide above was last modified on December 1, 2012 and I was working with Exchange 2016, I went ahead to try and find a more updated guide but was unable to find one so I went ahead and used the instructions in the older guide.  The following are the results from my tests.

Begin by reviewing the DAG configuration with the following cmdlet:

Get-DatabaseAvailabilityGroup <dagName> | FL *network*

The following is an example of the output from the cmdlet:

Get-DatabaseAvailabilityGroup 16dag | FL *network*

NetworkCompression : InterSubnetOnly

NetworkEncryption : InterSubnetOnly

ManualDagNetworkConfiguration : False

NetworkNames : {}

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The two configuration settings we’re interested in are:

  • NetworkCompression
  • NetworkEncrytion

More information about these two settings can be found in the following TechNet article:

Managing database availability groups
https://technet.microsoft.com/en-us/library/dd298065(v=exchg.150).aspx

In order to allow the Riverbed to accelerate the traffic, these two configuration settings need to be disabled.  As a test, I disabled NetworkEncryption first with the following cmdlet:

Set-DatabaseAvailabilityGroup 16dag -NetworkEncryption disabled

The following is the output and configuration settings of the DAG after the change:

Set-DatabaseAvailabilityGroup 16dag -NetworkEncryption disabled

Get-DatabaseAvailabilityGroup 16dag | FL *network*

NetworkCompression : InterSubnetOnly

NetworkEncryption : Disabled

ManualDagNetworkConfiguration : False

NetworkNames : {}

image

With NetworkEncryption disabled, the Riverbed was able to provide approximately 16% reduction of data:

imageimage

After performing the above test, I proceeded to disable NetworkCompression:

Set-DatabaseAvailabilityGroup 16dag -NetworkCompression disabled

Get-DatabaseAvailabilityGroup 16dag | FL *network*

NetworkCompression : Disabled

NetworkEncryption : Disabled

ManualDagNetworkConfiguration : False

NetworkNames : {}

image

With both NetworkCompression and NetworkEncryption disabled, the Riverbed was able to provide approximately 61% reduction of data:

imageimage

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