When optimising cloud costs, there are several options available. One of the most common Google Cloud discount is SUD. Sustained Use Discounts (SUD) are automatically applied discounts for using specific Compute Engine resources for a significant portion of the billing month. Discounts can reach up to 30% and do not require additional commitment. They apply automatically when you meet the requirements.
Compute Engine discounts
Discounts for sustained use of Compute Engine apply to resources used for over 25% of the billing month. The requirement is that these resources don’t get other discounts, such as Committed Use Discounts (CUD).
What does this mean?
Simply put, using a particular resource for one-fourth of the billing month will automatically qualify you for the SUD discount. The discount applies to each additional hour of using that resource and can go up to 30% of the net cost of resources for virtual machine (VM) instances running throughout the month.
Which resources are eligible for SUD?
You can expect Sustained Use Discounts for:
- Virtual Central Processing Units (vCPU) and memory for custom and predefined general-purpose machine types,
- Virtual CPUs and memory for compute-optimized machine types,
- Virtual CPUs and memory for memory-optimized machine types,
- Virtual CPUs and memory for sole-tenant nodes,
- Premium costs for sole-tenant nodes, even if the vCPUs and memory in those nodes are covered by CUD (Committed Use Discounts),
- All GPU devices except NVIDIA A100 and L4 graphics processors.
How much is the SUD discount?
Depending on resources and machine types, the SUD discount can be either 20% or 30%. Here is the breakdown:
20% SUD Discount
This discount level applies to:
- All predefined and custom N2 and N2D general-purpose machine types,
- All N2 and N2D general-purpose node types with exclusive tenancy,
- All C2 compute-optimized machine types,
- All C2 nodes with exclusive tenancy optimized for computation.
30% SUD Discount
This discount level applies to:
- All predefined and custom N1 general-purpose machine types,
- All N1 general-purpose nodes with exclusive tenancy,
- All M1 and M2 memory-optimized machine types,
- All M1 and M2 nodes memory-optimized,
- fq-micro and g1-small machines with shared cores,
- All graphics processors except NVIDIA A100 and L4 types.
How to enable Sustained Use Discounts?
You don’t need to do anything to activate SUDs. They apply automatically.
Limitations of Sustained Use Discounts
It’s essential to note that SUDs do not apply to virtual machines created using App Engine and Dataflow. They are only applicable to VMs created by Compute Engine and Google Kubernetes Engine.
How are SUDs calculated?
At the end of each month, Compute Engine automatically calculates the discount value and includes it in the resource costs. You can check this in the monthly cost table report for your billing account in the Google Cloud console.
Compute Engine treats the discount as a negative cost compensating for monthly resource usage costs. This means you can only use it in the month it is obtained.
Long-term use discounts for incremental usage are applied after reaching specific usage thresholds. In practice, you only pay for the number of hours you use the virtual machine – Compute Engine automatically provides the best price. The chart below shows how the effective discount increases with usage.
Cloud cost optimisation strategies
To find out how you can fully leverage cost optimisation opportunities, schedule a chat with our cloud architect. Find out if you are incurring unnecessary costs using Google Cloud.
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