Skip to main content

Fusion Snapshots

Fusion Snapshots enable checkpoint/restore functionality for Nextflow pipeline processes running on cloud Spot/preemptible instances. When a cloud provider reclaims an instance, Fusion Snapshots creates a checkpoint of the running process and restores it on a new instance, allowing the process to resume exactly where it left off.

Key benefits of Fusion Snapshots include:

  • Cost savings: Use Spot instances without risk of lost work.
  • Time efficiency: Resume from interruption point instead of restarting tasks.
  • Resource optimization: Avoid recomputing completed work.
  • Automatic operation: Your pipelines require no code changes.

Cloud provider support​

Fusion Snapshots is available for the following cloud providers:

Incremental snapshots​

Incremental snapshots optimize performance by capturing only changed memory pages between checkpoints. This reduces snapshot time and data transfer. Fusion Snapshots automatically perform incremental snapshots on x86_64 instances.

Key features of incremental snapshots include:

  • Pre-dumps: Captures only changed memory pages since the last checkpoint.
  • Full dumps: Complete process state captured periodically.
  • Automatic: Enabled by default, no configuration needed.
  • Efficient: Reduces checkpoint time and data transfer.

How Fusion Snapshots work​

Fusion Snapshots use CRIU (Checkpoint Restore in Userspace) to capture the complete state of a running process, including:

  • Process memory
  • Open files and file descriptors
  • Process tree and relationships
  • Execution state

When the system detects a Spot instance interruption:

  1. The system freezes the process and creates a snapshot of its state.
  2. Snapshot data is kept in sync with remote object storage via Fusion.
  3. On a new instance, the process state is downloaded and restored.
  4. The process continues execution from the exact point it was interrupted.

Get started​

To get started with your cloud provider, see: