http://blogs.technet.com/b/exchange/archive/2013/01/14/managing-oab-in-exchange-server-2013.aspx
Check this
Hi,
We can run the following command to check the OAB Generation Schedule in your Exchange 2013:
Get-MailboxServer MBX1 | fl "oab"
The OABGeneratorWorkCycle parameter specifies the time span in which the OAB generation on the Mailbox server will be processed. The default value is 8 hours.
The OABGeneratorWorkCycleCheckpoint parameter specifies the time span at which to run OAB generation on the Mailbox server. The default value is 1 hour.
We can use Set-MailboxServer cmdlet to customize OAB Generation Schedule:
Set-MailboxServer MBX1 -OABGeneratorWorkCycle 01.00:00:00 -OABGeneratorWorkCycleCheckpoint 04:00:00
For more information about this, please refer to:
https://technet.microsoft.com/en-us/library/Bb124719(v=EXCHG.150).aspx
http://blogs.technet.com/b/exchange/archive/2013/01/14/managing-oab-in-exchange-server-2013.aspx
Regards,