Is performance isolated from other tenants?
In Oracle Cloud Infrastructure (OCI), performance isolation is a core architectural principle. Unlike traditional "Generation 1" clouds that often struggle with the "noisy neighbor" effect, OCI was designed with a security-first, non-oversubscribed architecture to ensure that the performance you pay for is the performance you get.
Here is how OCI achieves performance isolation:
This is OCI’s "secret sauce." In traditional clouds, the hypervisor (on the main CPU) handles network and storage traffic for all VMs on that host. If one VM has a massive traffic spike, it eats up CPU cycles, slowing down every other VM on that box.
How OCI is different: OCI moves network and storage virtualization to a dedicated hardware card (a custom SmartNIC) outside the main server.
The Result: Your VM’s CPU never has to compete with its neighbors for "overhead" tasks. Network and storage I/O are processed independently of the main processor, providing deterministic performance.
Many cloud providers sell more "vCPUs" than they actually have physical cores, betting that not everyone will use 100% of their power at once. When everyone does use it, performance drops.
OCI’s Policy: Oracle does not oversubscribe compute or memory. If you rent 4 OCPUs, those represent physical CPU cores (or dedicated hardware threads) reserved exclusively for your instance.
The Result: You won't experience a "slowdown" just because another customer on the same physical hardware is running a heavy batch job.
For workloads where even the tiny risk of a hypervisor is unacceptable, OCI offers Bare Metal instances.
Physical Isolation: You rent the entire physical server. There is no hypervisor and no other tenants.
The Result: You have 100% of the hardware, memory bandwidth, and network interfaces to yourself. This is the highest level of performance isolation available in any cloud.
OCI uses a flat, non-blocking network design with Layer 2 isolation.
How it works: Each tenant’s Virtual Cloud Network (VCN) is isolated at the hardware level.
The Result: A "noisy neighbor" cannot saturate the network switch in a way that affects your data throughput. Your bandwidth is protected by the underlying network fabric.
In many clouds, you’ll see a metric called "CPU Steal Time," which shows how much of your CPU was "stolen" by the hypervisor to serve other tenants. In OCI, because of off-box virtualization and no oversubscription, you will typically see 0% CPU Steal, ensuring your application runs at full speed 24/7.