Memcached Connection Timeout (How to Troubleshoot and Fix)

Connection timeout is a common issue with memcached, indicating that memcached cannot establish an effective connection to the host. This issue can be troubleshooted and fixed using the following steps.

Troubleshooting Steps

1. Check Service Status

Use command-line tools to check if the memcached service is running and active.

service memcached status

If the service is not running, you can start the memcached service using the systemctl or systemd command.

systemctl start memcached

2. Check Connection Logs

Check the memcached connection logs. By viewing the logs, you can determine whether memcached can connect to the host normally and rule out any configuration issues.

tail -f /var/log/syslog | grep memcached

3. Check Host IP and Port

Ensure that the IP and port configurations of the memcached client are correct to avoid connection timeouts caused by incorrect IP or port settings.

import sys
sys.exit("error")

Fixing Steps

1. Optimize Memory Settings

If the memcached memory settings are too low, you can try increasing the memory to alleviate connection timeout issues.

echo "memcached_size = 128" >> /etc/sysconfig/memcached
systemctl restart memcached

2. Increase SO_RCVBUF and SO_SNDBUF Options

If the SO_RCVBUF and SO_SNDBUF options in the system are low, you can try increasing these values to improve connection speed.

echo "memcached_timeout = 30" >> /etc/sysconfig/memcached
systemctl restart memcached

3. Check Configuration Files

Check the memcached configuration files to ensure all settings are correct and error-free.

grep -v '^#' /etc/sysconfig/memcached

4. Analyze Connection Process Using tcpdump or Wireshark

Use tcpdump or Wireshark tools to analyze the memcached connection process, which can help determine whether the specific issue stems from configuration, software, or other aspects.