About Machine Images and Shapes

A machine image is a template of a virtual hard disk of a specific size with an installed operating system. A shape is a resource profile that specifies the number of OCPUs and the amount of memory to be allocated to an instance in Oracle Compute Cloud Service. The shape determines the type of disk drive that your instance uses.

When you select a shape, your instance is created with the corresponding number of Oracle Compute Units (OCPUs). An OCPU provides CPU capacity equivalent to one physical core of an Intel Xeon processor with hyper threading enabled. Each OCPU corresponds to two hardware execution threads, known as vCPUs, as shown in the following figure.


OCPUs on an Intel Xeon processor

A wide range of shapes is available to help you select a combination of processing power and memory for your instances that best suits your business requirement. The smallest general purpose shape provides 7.5 GB memory with a single OCPU. Larger shapes provide more OCPUs with correspondingly higher memory. If you need more memory per OCPU, select a high-memory shape.

  • While selecting the shape for an instance, consider the nature of the applications that you plan to deploy on the instance, the number of users that you expect to use the applications, and also how you expect the load to scale in the future. Remember to also factor in the CPU and memory resources that are necessary for the operating system.

  • Select a shape that meets the requirements of your workload with a sufficient buffer for intermittent spikes in the load. If you’re not sure what shape is appropriate for an instance, then start small, experiment with a representative workload, and then settle on a shape. This approach may help you achieve an optimal trade-off between resource allocation and performance.

The following tables list the shapes that are currently available in Oracle Compute Cloud Service.

General Purpose Shapes

Shape OCPUs vCPUs Memory (GB)

OC3

1

2

7.5

OC4

2

4

15

OC5

4

8

30

OC6

8

16

60

OC7

16

32

120

High-Memory Shapes

Shape OCPUs vCPUs Memory (GB)

OC1M

1

2

15

OC2M

2

4

30

OC3M

4

8

60

OC4M

8

16

120

OC5M

16

32

240