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Power governor

Power Governor Settings

The performance and stability of MooseFS—especially on Master Servers - greatly depend on predictable and consistent CPU behavior. To avoid performance degradation caused by dynamic frequency scaling or power-saving features, it’s important to configure the CPU power governor appropriately.

For Master Servers, we strongly recommend setting the CPU power governor to performance mode. This ensures that the CPU always runs at its maximum frequency, providing fast response times for metadata operations and reducing the risk of latency spikes.

If available, use the tuned service to manage power and performance profiles easily.

  1. Install the tuned package if it is not already installed:

    apt install tuned            # For Debian/Ubuntu-based systems
    yum install tuned            # For RHEL/CentOS/Rocky/AlmaLinux
    dnf install tuned            # For newer RHEL-based distributions

  2. Start and enable the tuned service:

    systemctl enable tuned
    systemctl start tuned

  3. Apply the performance profile:

    tuned-adm profile performance

This automatically adjusts the system to prioritize maximum CPU performance.

Manual Power Governor Adjustment (Alternative)​

If you don't use tuned, you can manually set the CPU governor:

  1. Check available governors:

    cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors

  2. Set the governor to performance for all CPUs:

    for cpu in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor; do
        echo performance > "$cpu"
    done
info

Note: You may also want to make this setting persistent by adjusting your system startup scripts.

Why This Matters​

The MooseFS Master Server handles metadata operations, which require fast and consistent CPU performance. Power-saving features like frequency scaling (ondemand, powersave) can introduce unpredictable delays, especially under sudden load spikes. Setting the CPU governor to performance helps maintain cluster responsiveness and stability under all conditions.