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Instance types and flavors#

VSC Tier1 Cloud provides several virtual machine instance types and flavors to fit different use cases. Each instance type provides several flavor sizes to give different combinations of CPU, memory, GPU and network resources.

Instance Types#

The following table provides the current main instance types available from the VSC Tier1 Cloud infrastructure:

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UPSv1 CPUv1 GPUv2 GPUv3
- AMD Epyc 7542 2.9GHz - Intel Xeon CPU E5-2670 2.60GHz - AMD Epyc 7542 2.9GHz - AMD Epyc 7542 2.9GHz
- 25Gbit Ethernet - 10Gbit Ethernet - 25Gbit Ethernet - 25Gbit Ethernet
- vCPU oversubscription 2:1
- Uninterruptible Power Supply (UPS) - Uninterruptible Power Supply (UPS)
- 1 full GPU NVIDIA Tesla4 - 1 full GPU NVIDIA Ampere A2

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Each instance type is appropriate for different workloads: (CPUv1) for regular CPU usage, (GPUvx) for GPU computations, or (UPSv1) for VMs that need to be connected to an uninterruptible power supply. VMs using UPS will keep up and running even if the datacenter suffers an unexpected power cut. (CPUv1) and (GPUv2) virtual machines are not supported by an UPS and will go offline when an unexpected power cut occurs.

VSC Tier-1 Cloud instance types also provide different kind of network performance specifications. All the instance types are able to connect to the available networks: public network, VSC network and shared filesystem network (NFS). Note that VSC and shared file system network access is only made available if explicitly requested in the project application.

VSC network gives an optimal path towards other VSC sites. This is ideal for high performance connections between different clusters and services within VSC. E.g. when you intend to do high data volume reshuffling between VMs and other Tier-1 components.

Cloud projects should request VSC network if they want to connect to VSC Data component (https://www.vscentrum.be/data) with iRODS and Globus from their Tier1 Cloud VMs.

On the other hand, the shared filesystem network is required by the OpenStack shared filesystem service (Manila) (see chapter 10 for more information).

Flavor Sizes#

A flavor size is a set of virtualized hardware resources to a virtual machine (VM) instance like system memory size (RAM), virtual cores (vCPUs) or the root filesystem size.

The flavor's root disk size is the amount of disk space used by the root (/) partition, an ephemeral disk that the base image is copied into (see section launch an instance for more information about VM persistent/non-persistent instances).

The flavor's root ephemeral storage is only used when booting from a non-persistent VM, but is not used when booting from a persistent storage volume or persistent VM. The flavor's root ephemeral size is not taken into account to calculate the project's local storage quota either. You can also create a persistent volume and choose the desired filesystem size for your persistent VM during the instantiation. VM persistent volumes could be resized later if that is necessary (see chapter launch an instance for more information).

VSC Tier-1 Cloud VM flavors are grouped by instance types (see table). Several flavor sizes are available for each instance type, differing in the number of allocated vCPUs, RAM and storage size. Every GPU flavor in addition allocates one full GPU card. The various VM flavors can be used in different combinations to fit different workload hardware requirements.

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Name RAM Root Disk vCPUs GPUs
CPUv1.nano 64Kb 1Gb 1 0
CPUv1.tiny 512Kb 10Gb 1 0
UPSv1.medium 4Gb 30Gb 2 0
UPSv1.large 8Gb 40Gb 4 0
UPSv1.2xlarge 60Gb 40Gb 16 0
GPUv2.small 2Gb 20Gb 1 1
GPUv2.medium 4Gb 30Gb 2 1
GPUv2.large 8Gb 40Gb 4 1
GPUv2.2xlarge 60Gb 40Gb 16 1
UPSv1.3xlarge 120Gb 80Gb 16 0
CPUv1.1_3xlarge 180Gb 80Gb 14 0
CPUv1.4xlarge 360Gb 80Gb 20 0
CPUv1.small 2Gb 20Gb 1 0
GPUv3.small 2Gb 20Gb 1 1
GPUv3.medium 4Gb 30Gb 2 1
GPUv3.large 8Gb 40Gb 4 1
GPUv3.2xlarge 60Gb 40Gb 16 1
CPUv1.medium 4Gb 30Gb 2 0
CPUv1.large 8Gb 40Gb 4 0
CPUv1.xlarge 16Gb 40Gb 8 0
CPUv1.2xlarge 60Gb 40Gb 16 0
CPUv1.3xlarge 120Gb 80Gb 16 0
CPUv1.1_2xlarge 60Gb 40Gb 8 0
UPSv1.small 2Gb 20Gb 1 0

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E.g. The GPUv2.large OpenStack flavor will instantiate a VM with 4 AMD Epyc 7542 2.9GHz vCPUs, with 1 NVIDIA Tesla4 GPU, 8GB of RAM, and a 40GB root disk.