Incident Report: Backend Down

Earlier this morning, at 04:38 UTC, one out of the twenty-two IMAP backends in production stopped serving its mail spool, showing Input/Output errors on its disk. Our Standard Operating Procedure is to examine log files, flush vm caches, stop the virtual machine, and start it back up again. This occurred at 05:48 UTC. The IMAP backend in question did not come back up cleanly.

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