IMAP is Hung, Single User Consuming All Resources (Doc ID 1448661.1)

Last updated on JULY 09, 2024

Applies to:

Symptoms

About every 2 hours, IMAP response time becomes very slow or completely hung and msprobe starts to report:

Restarting the store allows it to work for another two hours.

Another symptom is when the CPU spikes to 20% as compared to another similarly loaded system which is only 10%.
- It is imapd processes which usually seems to be using the most CPU.
- Also seeing more Q "mailbox is busy" messages than normal.
- It is not entirely isolated, but there is one user getting a lot more "mailbox is busy" than others and not receiving as much mail as others. Enabled telemetry for that user.
- This user was identified as the culprit of the imapd process CPU spikes.
- At one point, the custom IMAP application had over 60 IMAP sessions open.

Changes

Cause

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