Oracle Linux: Introduction to CPU Hotplug (Quick Summary)

CPU Hotplug in Oracle Linux allows you to dynamically enable or disable CPU cores in a running system—without requiring a reboot. This is especially useful in virtualized and cloud environments where workloads fluctuate.

🔍 Key Points:

• ✅ Hotplug Support is included in the Unbreakable Enterprise Kernel (UEK) and enabled by default.

• 🛠️ You can manage CPU state using simple sysfs commands:

  echo 0 > /sys/devices/system/cpu/cpuX/online  # offline
  echo 1 > /sys/devices/system/cpu/cpuX/online  # online
  

• 🔒 Security-conscious systems can restrict CPU hotplug operations using procfs and system security modules like SELinux or AppArmor.

• 💡 Useful for performance tuning, resource scaling, and testing failover behavior without downtime.

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Bottom Line:
CPU Hotplug gives administrators more control and flexibility over CPU resource allocation—supporting smarter, dynamic infrastructure management in Oracle Linux.

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