How to truncate logs on passive databases on a DAG Server (4038112)

How to truncate logs on passive databases on a DAG Server

You are protecting a node on an Exchange DAG spread over multiple servers that contains both active and passive exchange databases or a node containing passive database copies. You notice that the logs are not truncated on the passive databases. You are looking a simple method to force a log truncation on the node containing both active and passive databases or a node containing passive databases only. You try to disable the Exchange Replica Writer from the Agent Transfer Settings in the Core GUI but both the Exchange Writer and the Exchange Replica Writers get disabled at the same time.

Windows Registry Disclaimer:

Quest does not provide support for problems that arise from improper modification of the registry. The Windows registry contains information critical to your computer and applications. Make sure you back up the registry before modifying it. For more information on the Windows Registry Editor and how to back up and restore it, refer to Microsoft Article ID 256986 “Description of the Microsoft Windows registry” at Microsoft Support.

PowerShell Scripting Disclaimer:

This script is provided "as is" for the purpose of illustrating how product tasks may be performed in conjunction with PowerShell. Support shall not be liable for any direct, indirect, incidental, consequential, or other damage alleged in connection with the furnishing or use of this script or of the principles it demonstrates. See PowerShell Scripting Support for more information.

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Solution:

This issue is resolved in Rapid Recovery 6.0.2. Support recommends upgrading to the most recent build of Rapid Recovery. 

Workaround:

1. Log in on the node where truncation needs to be performed
2. Open RegEdit and navigate to HKEY_LOCAL_MACHINE\Software\Microsoft\ExchangeServer\v14\Replay\Parameters
3. If not already present, create a new Reg_Dword registry value: EnableVSSWriter and set it to 0 
4. Restart the  Microsoft Exchange Replication service (MSExchangeRepl) service Restarting this service does not affect Exchange functionality.
5. After the backup has been performed, set the HKEY_LOCAL_MACHINE\Software\Microsoft\ExchangeServer\v14\Replay\Parameters\EnableVSSWriter value to 1 andrestart the Exchange Replication service (MSExchangeRepl) again.

PowerShell:

To simplify the operation a PowerShell script has been created. 
The script checks the value of HKEY_LOCAL_MACHINE\Software\Microsoft\ExchangeServer\v14\Replay\Parameters\EnableVSSWriter. If the value does not exist it creates it. The value is toggled from 0 to 1 and back at every run of the script.

The script can be renamed to pretransferscript.ps1 and another copy of it to posttransferscript.ps1 and copied to C:\ProgramData\AppRecovery\Scripts on the agent (folder may need to be created) to automatize the Exchange Replica Writer suspension for every snapsot taken via AppAssure.
The code of the script is shown below between horizontal lines and attached to the KB.

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function private:test-registryvalue {
param (
[parameter(Mandatory=$true)]
[ValidateNotNullOrEmpty()]$Path,
[parameter(Mandatory=$true)]
[ValidateNotNullOrEmpty()]$Value
)
try {
Get-ItemProperty -Path $Path | Select-Object -ExpandProperty $Value -ErrorAction Stop | Out-Null
return $true
}
catch {
return $false
}
}

#toggle the Exchange Replica Writer
$regpath = "HKEY_LOCAL_MACHINE\Software\Microsoft\ExchangeServer\v14\Replay\Parameters"
$regvalue = "EnableVSSWriter"
$replicaservice="MSExchangeRepl"

#create value if not present
if(!(test-registryvalue -path "Registry::$($regpath)" -value "$($regvalue)")){
if(!(test-path "Registry::$($regpath)")){ New-Item -Path "Registry::$($regpath)" -force;
}
New-ItemProperty -Path "Registry::$($regpath)" -name $regvalue -Value 0 -PropertyType "DWord" 
}
$check = (Get-ItemProperty -Path "Registry::$($regpath)" -name $regvalue -ErrorAction Stop).($regvalue)
if ($check -eq 0){$value=1}
switch ($check)
{
0 {$value = 1}
1 {$value = 0}
default {Write-Host "`r`n$($regpath)\$($regvalue) has the invalid value of $check. Exiting..."; exit}
}

set-itemproperty -Path "Registry::$($regpath)" -Name $regvalue -Value $value 

(Get-ItemProperty -Path "Registry::$($regpath)" -name $regvalue -ErrorAction Stop).$regvalue

restart-service $replicaservice

Write-Host "Done!"

 

D-27658

DisableReplicaWriter