While cloud computing is often seen as "fixed" configurations, Oracle Cloud Infrastructure (OCI) offers a surprising level of low-level hardware customization before you even click "Deploy."

Depending on whether you are renting a Virtual Machine or Bare Metal, you have different levels of "under-the-hood" control.

1. Bare Metal: Deep BIOS Customization

For Bare Metal servers, OCI provides a feature called Advanced BIOS Settings. This allows you to tune the physical hardware to match your specific performance needs before the server is even turned on:

• SMT (Simultaneous Multithreading): You can choose to Enable or Disable hyper-threading. Disabling it is common for HPC workloads where you want a single, powerful physical core per thread to avoid latency jitter.

• NUMA Node Configuration (NPS): On AMD shapes, you can set the "Nodes Per Socket" (NPS0, NPS1, NPS2, or NPS4). This changes how the CPU accesses memory, allowing you to optimize for massive data throughput or ultra-low latency.

• Core Scaling: You can choose to enable only a fraction of the physical cores (25%, 50%, or 75%). While you still pay for the full server, this is a strategic move to reduce software licensing costs (e.g., for Oracle Database) while keeping the full memory and network bandwidth of the machine.

2. Virtual Machines: The "Slider" Customization

For VMs, customization is focused on Flexible Shapes, which eliminate the standard "Small/Medium/Large" constraints:

• OCPU & RAM Decoupling: You can choose exactly 3 OCPUs and 42.5 GB of RAM. You aren't forced to jump from 4 cores to 8 cores just to get more memory.

• Boot Volume Performance: You can set the "Volume Performance Units" (VPUs) for the boot drive during deployment. You can opt for a "Higher Performance" boot drive if your application does a lot of disk-heavy logging.

3. Image & OS-Level Customization

Before deployment, you can customize the "Software Hardware" via:

• Bring Your Own Image (BYOI): You can upload your own customized OS image (QCOW2 or VMDK) that contains specific kernel tweaks, security patches, or drivers.

• Cloud-Init Scripts: You can provide a "User Data" script. The moment the hardware powers on, it will automatically run your script to install software, mount drives, or configure the network.

Comparison: What can you change?

Pro-Tip: "Shielded Instances"

During deployment, you can also customize the security hardware. By checking the Shielded Instance box, OCI uses Secure Boot, Measured Boot, and a Trusted Platform Module (TPM) to ensure the firmware hasn't been tampered with before your OS loads.