Asynchronous Copy is a high-throughput copy command built for large data migrations at higher speed. It uploads files individually and confirms each upload in the background using tokens, rather than batching files together.
It involves lower memory usage and can run on machines with as low as 16 GB RAM / 8 CPU cores.
Prerequisites
Before enabling the asynchronous mode, verify the following:
- Internet speed and disk read speed must both be at least 1 Gbps.
- Minimum 8 CPU cores are recommended.
- If a migration job was already created before enabling the feature, it will be forced to re-run the scan.
- Ensure browser cache has been cleared before starting the command.
Best Practices
- Do not enable Asynchronous Mode if the virtual machine’s internet or disk read speed is below 1 Gbps. Lower speeds result in higher timeout errors.
- Async Copy performs best when both internet and disk read speeds exceed 3–4 Gbps.
- At higher speeds, 1–2 migration jobs on a single machine is recommended for optimal performance.
Enable Asynchronous Mode on Migration Job
- Open the migration job and navigate to the Advanced Options -> Asynchronous Mode
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Turn ON Enable Asynchronous Mode and click on Save.
The changes will be saved.
Run Asynchronous Copy
- Open the migration job details and click on Migration Job actions -> Migrate Data
- Click on Migrate Data to start async copy
- The migration job will show Async copy in progress.
- Once the copy phase is complete, the job status will be updated as Async copy succeeded. Users can continue with the rest of the migration job actions.
Limitations
- On-source or on-the-fly sanitization is not available during Async Copy. During the copy phase, only valid files are uploaded. Files that require sanitization (typically less than 0.5% of the overall data) are skipped and are processed during the subsequent true-Up.
- Empty folder creation is not available during Async Copy. During true-Up, a prompt is displayed to enable or disable empty folder creation. If enabled, empty folders from the source are created in the destination. If disabled, they are skipped.
- Files and folders with future timestamps are not processed during the Async Copy phase. During true-Up, a prompt is displayed to enable or disable future timestamp handling, and the operation runs based on the selected option.
- The option to run validation is not displayed immediately after an Async Copy. During true-Up, auto-validation can be enabled, and validation runs based on the selected option.
- If Async copy is configured in a custom config file, this value will not be applied during migration runs. The flag will still be visible in the agent config file, but it does not influence migration behavior.
- Async Copy is not supported for Power Users. Although the option remains available, enabling Async Copy causes all file uploads from CFS to be marked as failed.
Additional Information
The complete documentation is available here, but the seven important resources are: