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How Does Offline Address Book (OAB) Works – Deep Dive (Part 3)

In previous Articles, Part1 and Part2 we have seen what is Outlook Offline Address(OAB) and how does it works.

In this Article, we will see how to change the Offline Address book Generation Schedule and Troubleshooting steps when issue comes

What is this Generation Schedule of Offline Address Book(OAB)? Offline Address Book(OAB) is the combinations of the address lists added in the offline address list distribution. ideally it is default Global Address List. In some Organizations Location based Address lists, Hierarchical based Address lists are created.

Mailbox Assistant Service is responsible for OAB Generation which queries changes every 8 Hours Once the Address lists added in the OAB and generates the latest OAB and keeps them in the Location: %ExchangeInstallPath%ClientAccess\OAB\ for the distribution and clients calls the virtual directories and gets the latest update. By Default 24 once clients calls for the OAB Changes.

8 HOURS is the default set for the OAB Genration. so any user changes gets updated 8 Hours once in the OAB and clients downloads it 24 Hours once. Hence that the Address book for the new users information takes minimum 24 hours to show in the Outlook Clients. even users tries to download manually, it is still takes 8 hours minimum.

if your organizations required to reduce the schedule, it is still possible. if you ask what is the impact?, there is no impact as long as you have very good connectivity between exchange servers and Global Catalog(GC) Servers.

How to see the current settings of the WorkCycle? Run the below command to see the current settings,

[xml]$diag=Get-ExchangeDiagnosticInfo -Server MBX1 -Process MSExchangeMailboxAssistants -Component VariantConfiguration -Argument “Config,Component=TimeBasedAssistants”; $diag.Diagnostics.Components.VariantConfiguration.Configuration.TimeBasedAssistants.OABGeneratorAssistant

Note: In Exchange 2016 CU3 or earlier, you need to run this command instead: [xml]$diag=Get-ExchangeDiagnosticInfo -Server MBX1 -Process Microsoft.Exchange.Directory.TopologyService -Component VariantConfiguration -Argument Config; $diag.Diagnostics.Components.VariantConfiguration.Configuration.MailboxAssistants.OABGeneratorAssistant

To reduce the Work Cycle Intervel, run the command below command to create New Settingsoveride Policy, New-SettingOverride -Name “OAB Generation Override” -Component TimeBasedAssistants -Section OABGeneratorAssistant -Parameters @(“WorkCycle=04:00:00”) -Reason “Generate OAB every 4 hours”

Now run the below command to enforce the new Policy created,

All done. Run the command to view the current settings applied. Get-ExchangeDiagnosticInfo -Process Microsoft.Exchange.Directory.TopologyService -Component VariantConfiguration -Argument Refresh

Note: So far done for the complete organization, If you have multiple datacenters and having the Multiple servers, you can still apply the server based settings you donot want to apply Org level using the same command with -Server Paremeter followed with Server name to apply. For more details, please refer this Article.

For more details on Offline Address Book (OAB) , Please refer the below Multi Part of articles

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