You can find a OAB Virtual Directory in IIS – in the Client Access Server The Request to the Client Access (OAB Virtual Directory) Proxies the request to the “Exchange Back End” (OAB Virtual Directory) which is a Mailbox Server Containing OAB Files where client downloads the OAB Files Offline Address Book Storage Location Offline Address book Stores its files to a “System Mailbox” Which is called as “Organizational Mailbox” Where if the database fails the Organization Mailbox can failover using Database availability Group. It looks the database which owns the Organization Mailbox and OAB files are copied over to the Disk in the appropriate Mailbox Server and it has been to the Client.Where OAB is no more a single point failure in Exchange 2013 To See which Organizational Mailbox is storing OAB files – You can see – “Organization Capability OABGen” Then Its Copied over to the disk in the Form of LZX files Default Location: (Differs if you install Exchange on a Different Drive) C:\Program Files\Microsoft\Exchange Server\v15\Client Access\OAB They will be copied to the disk in the Form of LZX files How to find the Offline Address book url , which is used for OAB Downloads From Outlook 2007 , Outlook 2010 and So on , Outlook Downloads Offline Address book using the OAB Url Web-Based (IIS) You got to Specify the External Url if you are going to use Outlook Anywhere using Set-Oab Virtual Directory Cmdlet To Find which OAB a User Downloads Go to a Client Machine Hold your Ctrl Key and Right Click on the Outlook icon – Click on Test Email Auto Configuraion Now Using Auto Discover , You can see the Offline Address book URL as listed below with the Correct Guid Value To Find the GUID Value of the Offline address book Client will Download their Own OAB depends upon their “Client Settings in Database Properties” If its not specified – By Default they will download the “Default Offline address book” Or If they have address book policies applied They would Download their own OAB respective to the Policy Now Depends on the Update Time “Organization Mailbox” will get updated on the Mailbox Server.
In all previous Exchange releases, OAB generation was bound to a specific Exchange server.The unbinding of OAB from a specific server allows the same OAB to be generated by multiple Mailbox servers.This new architecture provides greater resiliency in OAB generation.The disadvantage with this approach was that only one server was configured for OAB generation, and it was a single point of failure.In Exchange 2013, the OAB is generated by each Exchange 2013 Mailbox server(s) that hosts a special type of arbitration mailbox, called organization mailbox.
In all previous Exchange releases, OAB generation was bound to a specific Exchange server.
The unbinding of OAB from a specific server allows the same OAB to be generated by multiple Mailbox servers.
This new architecture provides greater resiliency in OAB generation.
The disadvantage with this approach was that only one server was configured for OAB generation, and it was a single point of failure.
In Exchange 2013, the OAB is generated by each Exchange 2013 Mailbox server(s) that hosts a special type of arbitration mailbox, called organization mailbox.
As we have discussed that deployment of DPM would be very useful if your server is hosted in DAG and you don’t want to let the server down for a little span of time.