Get-EXOMailboxPermission vs Get-MailboxPermission

Jesus Chao 141 Reputation points


We have an Azure Automation runbook that is getting mailbox permissions in EXO. We have about 4000 mailboxes. When we use Get-ExoMailboxPermission against all the mailboxes, the Azure Automation runbook takes well over 3 hours to complete - which causes the runbook to fail because there is a 3 hour limit on running runbooks. However, if we use the old cmdlet Get-MailboxPermission, it takes about 50 minutes.

Why is there such a huge difference in performance? It's difficult to justify transitioning to EXO cmdlets when it takes 3 times as long. Is anyone else experiencing the same?


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Azure Automation
Azure Automation
An Azure service that is used to automate, configure, and install updates across hybrid environments.
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A family of Microsoft task automation and configuration management frameworks consisting of a command-line shell and associated scripting language.
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  1. Yuki Sun-MSFT 40,916 Reputation points

    Hi @Jesus Chao ,

    EXO cmdlets claim to be faster and reliable,(See statement in this link so it doesn't make sense to me either that it took much longer to complete in your case.

    I've also tested in my lab tenant by running the cmdlets below. Although I have only a dozen of mailboxes, per my observation, EXO cmdlets are seemingly a little bit faster than the old one.

     Get-EXOMailbox -ResultSize unlimited | Get-EXOMailboxPermission
     Get-Mailbox -ResultSize unlimited | Get-MailboxPermission

    For your situation, could you try testing by running the two cmdlets exclusively in Windows PowerShell and check how it goes. This might help eliminate the impact of Azure Automation.

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