Differences of bare metal and virtual machines

Bare metal

Bare metal clusters provide direct access to physical hardware for greater control and customization of the environment. This includes but is not limited to:

  • physical CPUs, not virtualized CPUs

  • no hypervisor overhead which requires host CPU and memory resources

  • ability to change symmetric multi threading (SMT) and NUMA BIOS settings

  • full access to local NMVe block devices to configure filesystems and RAID

  • enhanced security by removing the hypervisor layer

Denvr Cloud has limited observability into bare metal hosts which which requires additional responsibility of the tenant to monitor and report system issues for analysis.

Virtual machines

Virtual machines provide access to GPUs and compute resources with a minor overhead required for the hypervisor. The primary benefits of virtualization, even for full nodes, are:

  • choice of operating system images to use during provisioning

  • 1-5 minutes to boot the instance (depends primarily on number of vCPUs assigned)

  • ability to resize allocated resources (CPU, memory disks) as requirements change

  • less likelihood of over-provisioning resources versus large bare metal hosts

  • usage of snapshots for backups and starting new instances

  • self-service management via Denvr Cloud console and APIs

Feature comparison

Performance

Bare Metal
Virtual Machines

Overhead

None

Hypervisor requires CPU and memory resources

Consistency

High consistency in performance

Potential variability in performance

Security

Bare Metal
Virtual Machines

Tenant isolation

✔️ Single tenant only

✔️ Single or multi-tenant

Multi-user access

May require additional software to manage user isolation and Quality of Service

Quality of service is enforced

Security risk

Lowest risk of cross-tenant impact

Higher risk due to shared infrastructure. Virtualization is a mature technology in use since the early 2000's.

Data privacy

✔️ Denvr has no mechanism to access the system, including for operational support

✔️ Denvr can monitor and maintain the system hardware instead of the user

Management

Bare Metal
Virtual Machines

Node types

✔️ Full node only

✔️ Allows customization of machine resources including single-GPU instances

Scalability

Full node only

Instance sizes can be changed dynamically without re-provisioning

Software and drivers

Denvr only installs the GPU and fabric drivers.

Pre-configured images are available with required software dependencies.

Time to launch

Slower

Fastest

Backup and restore

Difficult to backup the operating system for recovery

Simple to snapshot, clone, copy, and duplicate machine images.

Last updated