The error message 'zimbra memcached is not running' occurs when the Memcached instance that is supposed to be running on the Zimbra mail server is not up and operational. Memcached is a popular open-source caching system that is used to speed up dynamic web applications by temporarily storing data in memory.
In this specific case, it means that the Zimbra mail server is unable to connect to the Memcached instance due to it being stopped or not running at all. This can happen due to various reasons such as server crashes, network issues, memory usage exhaustion, or misconfigurations.
To resolve the 'zimbra memcached is not running' error, you can try one of the following solutions:
Start the Memcached Service: Check if Memcached service is installed on your server, if it is installed use command-line utility
systemctl start memcached or
/etc/init.d/memcached start to start the service if it is stopped.
Restart Memcached: If the service is already running but experiencing issues, restarting Memcached may help solve the problem, use command-line utility
systemctl restart memcached or
Check the Configuration: Ensure that the Memcached configuration file is correctly set up and pointing towards the correct IP addresses and ports.
Check for Memory Usage Issues: In case the Memcached instance is running but not functioning as expected, check the memory usage and ensure that there is enough available memory. You can also increase the memory limit by adjusting the caching settings.
Check The Network Connection: Verify that the network connection between the Zimbra mail server and the Memcached instance is stable and functional. You can try pinging the Memcached server from the Zimbra server to verify that the connection is up and running.
By utilizing the above solutions, you should be able to resolve the 'zimbra memcached is not running' error and ensure that your Zimbra mail server is operating optimally.