Configure Systemd TimeoutStartSec¶

If your MySQL service takes too long to start, it might be due to a large buffer pool or a significant amount of data synchronization. You can either increase the MySQL service TimeoutStartSec option or disable the option.

We recommend that yoou treat TimeoutStartSec as a diagnostic and management tool, not as a permanent fix for underlying performance problems.

The following are the benefits of using TimeoutStartSec:

Prevents services from hanging indefinitely during startup
Provides controlled startup time management
Stops runaway processes from consuming system resources
Offers flexibility in handling complex service initialization
Helps detect and manage slow-starting database services
Enables precise control over service launch duration

The following are the potential drawbacks of using TimeoutStartSec:

Arbitrarily low settings might interrupt legitimate slow startups
Requires careful tuning for different system configurations
Can mask underlying performance or configuration issues
Might hide complex initialization problems
Demands ongoing monitoring and adjustment

You should test and use TimeoutStartSec in the following situations:

Large databases with extensive initialization requirements
Servers with limited resources
Complex clustered database environments
Systems with significant data synchronization needs

Use the following techniques to test the option:

Start with generous timeout values
Gradually reduce timeout as you understand your system’s behavior
Monitor service startup patterns
Use logging to understand initialization bottlenecks
Test configuration changes in staging environments

Check the current timeout¶

Check the current timeout with the following:

$ systemctl show mysql.service -p TimeoutStartUSec

Expected output

TimeoutStartUSec=10min

Edit the command¶

The following command opens an editor:

$ sudo systemctl edit mysql.service

In the text editor, overwrite the TimeoutStartSec configuration:

[Service]
TimeoutStartSec=900s

For the edited change to take effect, run the following command:

$ sudo systemctl daemon-reload

After reloading the system, the value is 15 minutes.

Expected output

TimeoutStartUSec=15min

Disable the option¶

To disable the option, change the value to 0:

[Service]
TimeoutStartSec=0

For the edited change to take effect, run the following command:

$ sudo systemctl daemon-reload

After reloading the system, the option is disabled.

Expected output

TimeoutStartUSec=infinity

Verify the change¶

After systemctl has been reloaded, verify your change.

$ systemctl show mysql.service -p TimeoutStartUSec