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Snapshots

Spicepod Example​

snapshots:
  enabled: true
  location: s3://some_bucket/some_folder/
  bootstrap_on_failure_behavior: warn
  params:
    s3_auth: iam_role

datasets:
  - name: some_table
    acceleration:
      engine: duckdb
      mode: file
      snapshots: enabled
      params:
        duckdb_file: /nvme/some_table.db

Overview​

Acceleration snapshots let Spice reuse a pre-built acceleration file on startup instead of waiting for a full refresh. When a dataset uses a file-mode acceleration engine (DuckDB or SQLite) and the local file is missing (for example on first boot or when using ephemeral NVMe storage), Spice downloads the most recent snapshot from object storage and moves the dataset straight to a ready state.

Preview

Acceleration snapshots are available in preview.

How it works​

  • On startup, Spice checks whether the file supplied in acceleration.params (for example duckdb_file) exists.
  • If the file is missing and snapshots are enabled, Spice looks under the configured snapshot location and downloads the newest snapshot for that dataset.
  • If no snapshot is available, the acceleration boots empty and refreshes from the source.
  • After each refresh, Spice writes a new snapshot unless the dataset is configured in bootstrap_only mode.

Snapshots are organized with Hive-style partitioning so they are easy to retain and prune. For a dataset named my_dataset, Spice writes files such as:

s3://some_bucket/some_folder/month=2025-09/day=2025-09-30/dataset=my_dataset/my_dataset_20250919T134522Z.db

The timestamp is recorded in UTC using ISO 8601 without punctuation.

Dedicated files only

Every accelerated dataset must write to its own file (for example, /nvme/my_dataset.db). Sharing a single file across multiple datasets is not supported.

Configure snapshot storage​

Snapshots are controlled with a new top-level snapshots block in the Spicepod. The location must point to a folder on S3 or the local filesystem. When the location is an S3 bucket, the configuration accepts any S3 dataset parameters under params.

snapshots:
  enabled: true
  location: s3://some_bucket/some_folder/ # Folder where snapshots are written
  bootstrap_on_failure_behavior: warn     # retry | fallback | warn
  params:
    s3_auth: iam_role                     # Defaults to iam_role for snapshots

Failure behavior​

bootstrap_on_failure_behavior controls what Spice does when it cannot load the most recent snapshot.

  • retry – keep retrying the newest snapshot until it succeeds.
  • fallback – try older snapshot files until one loads successfully.
  • warn – log a warning and continue with an empty acceleration. (Default.)

Enable snapshots per dataset​

Each dataset opts into snapshotting through the acceleration.snapshots field. Four modes are available:

  • enabled – download snapshots on startup and write a new snapshot after each refresh.
  • bootstrap_only – only download snapshots; never write new ones.
  • create_only – write new snapshots after refreshes, but never download them on startup.
  • disabled – disable snapshot usage for this dataset. (Default.)

Example Spicepod configuration:

snapshots:
  enabled: true
  location: s3://some_bucket/some_folder/
  bootstrap_on_failure_behavior: warn
  params:
    s3_auth: iam_role

datasets:
  - from: s3://some_bucket/some_table/
    name: some_table
    params:
      file_format: parquet
      s3_auth: iam_role
    acceleration:
      enabled: true
      engine: duckdb
      mode: file
      snapshots: enabled
      params:
        duckdb_file: /nvme/some_table.db
Readiness with append refreshes

Append-mode accelerations that define a time_column wait to report ready until the first append refresh completes after snapshot bootstrap. This keeps the dataset out of rotation until the freshest data is available while still benefiting from the snapshot-assisted startup. See Fast Cold Starts for additional context.

Best practices​

  • Pair with ephemeral storage: Deployments commonly place the acceleration file on fast ephemeral disks (such as NVMe instance storage) while relying on snapshots for persistence across restarts.
  • Align retention policies: Apply an object storage lifecycle rule that mirrors the desired snapshot retention policy.
  • Monitor bootstraps: Track warning logs emitted when Spice falls back to an empty acceleration so operators can respond quickly if snapshot loading fails.

For the full reference, see snapshots in the Spicepod specification and acceleration.snapshots.