Category Archives: Safety Net

Modifying the log file size for safety net on Exchange 2013

In this article lets see how to change the values of safety net in Exchange 2013.

Transport Dumpster  is replaced with Safety Net in Exchange 2013 unlike the earlier versions.It prevents data loss by maintaining a queue of successfully delivered messages. Unlike the earlier version of transport dumpster it also holds emails of mailbox that is not a member of DAG and also public folder mailboxes.

From exchange 2013 safety net does not mandatory requires DAG.Now the safety net is no more single point of failure since it has 2 queues primary safety net and shadow safety net.

Because of this we will notice huge difference in the log file size compared  to 2010 in 2013.

This is because of the safety net holding primary safety net and shadow safety net information in the queue.

So where does this Safety Net Queue Location resides ?

There is no dedicated Safety Net location in Exchange 2013 and it stores the messages in the same transport queue that is located in the mailbox server.

All the different queues are stored in a single ESE database. By default, this queue database is located on the transport server at %ExchangeInstallPath%TransportRoles\data\Queue.

Below is the location of the safety net queue in exchange 2013

Transport Queue

At times there might be a situation where the safety net queue will grow abnormally. Below are the steps that can be followed when we run into these kind of scenarios.

First we can create a new transport queue.

In-order to do that follow the below steps.

On each server with a large mail.queue file:
a. Stop the MSExchangeTransport service.
b. Delete the mail.que file.
c. Start the MSExchangeTransport service.

Also we can troubleshoot safety net by changing the safety net hold time.

By Default the hold period for the safety net will be 2 days. If you wish to change these values follow the below procedure.

To check the safety net hold time run the below command
Get-TransportConfig | ft name,Safety*


In-order to change the value run the below command

Set-TransportConfig –SafetyNetHoldTime 1.00:00:00


You will get the above warning once you run the above command. So you need to ensure that the SafetyNetHoldTime’ needs to Exceed ‘ReplayLagTime. Keep this in mind that  you need to plan this according to your lag copies. You need not worry about this if you do not have any lag copies.

Now there is something a value called message expiration time out. This is actually the message in the shadow safety that can remain the queue before it expires.

To see this value run the below command.

Get-TransportService |ft name,messageexpiration*


To change this value run the below command


These values can be changed from the EAC as well

Inroder to change the value through EAC perform the following steps

Open EAC- Click on mail flow tab – Click on receive connectors

Click on more and click on organizational transport settings


Below you have the option to change the value of the safety net hold time as shown


Hope this article will help to change the safety net value in Exchange 2013.


Sathish Veerapandian

Technology Evangelist

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