We’re planning to migrate several Oracle Database instances to OCI and trying to decide between bare metal (BM) shapes and VM shapes. Our workloads are mostly OLTP with some batch processing overnight.
I understand bare metal gives dedicated hardware, but VMs offer more flexibility. For Oracle Database specifically, what are the real-world performance differences? We’re looking at BM.Standard2.52 vs VM.Standard2.24 options. Cost is obviously a factor - bare metal is more expensive per hour, but we need to factor in Oracle licensing costs too since it’s per core.
Has anyone done comparative benchmarks or have experience running production Oracle databases on both? Interested in actual performance numbers, not just theoretical specs.
We ran extensive benchmarks last year comparing BM.Standard2.52 and VM.Standard2.24 for Oracle 19c. For OLTP workloads (using HammerDB), bare metal showed about 15-20% better throughput at peak load, mainly due to reduced I/O latency and no hypervisor overhead.
However, the cost difference is significant. BM.Standard2.52 runs about $3.32/hour vs VM.Standard2.24 at $1.632/hour. For 24x7 operation, that’s roughly $29K vs $14K annually just for compute. If your workload doesn’t consistently max out resources, VMs are more cost-effective.
One more licensing consideration - OCI offers BYOL (Bring Your Own License) and License Included options. If you’re using License Included, Oracle charges per OCPU hour, making VMs significantly cheaper since you only pay for what you provision.
With BYOL on bare metal, you might be forced to license all cores even if you partition the workload. Check with Oracle licensing team, but typically you need to license the entire physical server unless you use hard partitioning (which isn’t available in cloud environments). This makes VMs much more attractive from a licensing compliance and cost perspective.
These are great points. Our workload analysis shows peak utilization around 60-70% of what a 24-core VM would provide, so we probably don’t need the full bare metal capacity. The licensing cost difference is substantial - we’re looking at Enterprise Edition with RAC, so that’s a huge multiplier.
What about I/O performance specifically? Our databases are heavily I/O bound with lots of random reads. Does bare metal show significant advantages there, or is VM performance with NVMe local storage good enough?
For I/O-intensive Oracle workloads, both bare metal and VM shapes with NVMe local storage deliver excellent performance. We measured around 200K-250K IOPS on VM.DenseIO2.24 (NVMe local SSDs) vs 300K-350K IOPS on BM.DenseIO2.52.
The difference is noticeable but not dramatic for most OLTP workloads. If you’re doing massive batch operations or data warehouse scans, bare metal pulls ahead. For typical OLTP with 60-70% utilization, VM shapes with local NVMe storage should meet your performance needs at half the cost. Use the savings for better DR/HA configuration.
Don’t forget about hardware isolation for compliance. If you’re in healthcare or financial services, bare metal provides physical isolation that some compliance frameworks require. VMs share underlying hardware even though they’re logically isolated.
Also consider failover scenarios. With VMs, you can quickly spin up a standby in another AD. With bare metal, provisioning takes longer (15-20 minutes vs 2-3 minutes for VMs). For DR planning, VMs offer faster recovery times unless you keep hot standby bare metal instances running, which doubles your costs.