Hohe CPU Last durch viele MAPI Zugriffe auf den Exchange Server.

Question

Mails werden in Outlook nur verzögert versendet. Kalendereinträge nicht synchronisiert. Neustart von Outlook hilft temporär. Webschnittstelle OWA funktioniert.

IIS: mapi/emsmdb Zugriffe, Time elapsed > 800000. Recycling hilft nur temporär, danach neuer Anstieg

Viele erfolgreiche (200) W3SVC POST logfile Einträge. Teilweise 50 pro Sekunde von einem Benutzerkonto.

EWS/Exchange von Apple Geräten und mapi/emsmdb von Outlook über Anonymous

CPU temporär über mehrere Minuten bei 100%. MSExchangeMAPIMailboxAppPool (w3wp.exe) springt von 8% auf 40%CPU, ebenso MAPIFrontEnd.

Nicht jeder Benutzer mit derselben Outlook Version verursacht das Problem.

Server 2016 + Exchange 2016, aktuelle Patches

Wie können die Zugriffe begrenzt werden? (throttling policies?)

Wie können die nicht getrennten MAPI Sessions getrennt werden? Ursachensuche?

Answer 1

Hello, @Paul,

Welcome to the Microsoft Q&A platform!

Since you posted your question in the English forum, I will answer your question in English, please understand the inconvenience caused.

Based on your description, you are dealing with a complex issue involving delayed email delivery, calendar synchronization problems, and high CPU usage on your Exchange server. Let's break down the steps to address these issues:

1. Delayed Email Delivery and Calendar Synchronization Issues

• Check Outlook Settings: Ensure that Outlook is configured correctly. Switching from Cached Exchange Mode to Online Mode might help.
• Clear Offline Items: In Outlook, right-click the Calendar folder, select Properties, go to the General tab, and choose “Clear Offline Items”.
• Update and Repair Office: Make sure your Office suite is up to date. You can also try repairing Office via Control Panel.

2. High CPU Usage

High CPU usage can sometimes be caused by add-ins. Try disabling all add-ins and then re-enable them one by one to identify if a specific add-in is causing the issue.

3. Throttling Policies

• Set Throttling Policies: You can use the Set-ThrottlingPolicy cmdlet (Set-ThrottlingPolicy (ExchangePowerShell) | Microsoft Learn) to modify the settings for a user throttling policy. This can help manage the load on your server by limiting the number of concurrent connections and the rate of requests.
• Message Rate Limits: Implement message rate limits and throttling options (Message rate limits and throttling | Microsoft Learn) to protect your Exchange server from being overwhelmed.

4. Disconnecting MAPI Sessions

• Disable MAPI Access: You can disable MAPI access to specific mailboxes using the Exchange admin center (EAC) or the Exchange Management Shell.
• End MAPI Sessions: To terminate MAPI sessions, you can cancel the registrations for all notifications, release all open objects, and call IMAPISession::Logoff.

For more instructions, please refer to:

1.Enable or disable MAPI access to mailboxes in Exchange Server | Microsoft Learn

2.Ending a MAPI Session | Microsoft Learn

5. Investigate Causes

• Analyze Logs: Review the IIS logs and Exchange logs to identify patterns or specific users causing the issue.
• Monitor Performance: Use performance monitoring tools to track CPU usage and identify processes that are consuming resources.

Should you need more help on this, you can feel free to post back. 

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If the answer is helpful, please click on “Accept answer” as it could help other members of the Microsoft Q&A community who have similar questions and are looking for solutions.

Thank you for your support and understanding.

Best Wishes,

Alex Zhang