AWS Snowball
User Guide

This guide is for the Snowball (50 TB or 80 TB of storage space). If you are looking for documentation for the Snowball Edge, see the AWS Snowball Edge Developer Guide.

Options for the snowball cp Command

Following, you can find information about snowball cp command options and also syntax guidelines for using this command. You use this command to transfer data from your workstation to a Snowball.

Command Option Description
-b, --batch


Significantly improves the transfer performance for small files by batching them into larger .snowballarchives files. Batching is on by default. You can change the following defaults to specify when a file is included in a batch:

  • By default, files that are 1 MB or smaller are included in batches. You can change this setting by specifying the --batchFileSizeInKBLimit option with a new maximum file size, in kilobytes. Maximum file sizes range from 100 KB to 1 MB. Files that are larger than the specified maximum file size are transferred to the Snowball as individual files and not included in any batches.

  • By default, batches hold up to 10,000 files. This limit can be changed by setting the --batchNumOfFiles option. The number of files in a batch can range from 5,000 to 100,000 files.

During import into Amazon S3, batches are extracted and the original files are imported into Amazon S3. Only .snowballarchives files that were created during the copy command with this option are extracted automatically during import.


On and set to false by default.

Calculates a checksum for any source and destination files with the same name, and then compares the checksums. This command option is used when a copy operation is resumed. Using this option adds computational overhead during your copy operation.


When this option isn't used, a faster comparison of just file names and dates occurs when you resume as copy operation.

-f, --force

On and set to false by default. This command option has two uses:

  • When used with a copy command, -f overwrites any existing content on the destination that matches the path and name of the content being transferred.

  • When used after a copy command is run, -f overrides the --resume command option. Instead, your copy operation is performed from the beginning again, overwriting any existing content on the destination with the same path and name.


The preceding use cases are not mutually exclusive. We recommend that you use -f with care to prevent delays in data transfer.

-h, --help

On and set to false by default.

Displays the usage information for the snowball cp command in the terminal.



Disables automatic batching of small files. If you're copying a directory, and you use this option, you must also use the --recursive option. This option is hidden. For performance reasons, we don't recommend that you use it unless your use case requires it.

-r, --recursive

On and set to false by default.

Recursively traverses directories during the snowball cp command's operation.

-s, --stopOnError

On and set to false by default.

Stops the snowball cp command's operation if it encounters an error.


The --batch option for the Snowball client's copy command is not supported for HDFS data transfers. If you must transfer a large number of small files from an HDFS cluster, we recommend that you find a method of collecting them into larger archive files, and then transferring those. However, these archives are what is imported into Amazon S3. If you want the files in their original state, take them out of the archives after importing the archives.

Snowball Logs

When you transfer data between your on-premises data centers and a Snowball, the Snowball client automatically generates a plaintext log and saves it to your workstation. If you encounter unexpected errors during data transfer to the Snowball, make a copy of the associated log files. Include them along with a brief description of the issues that you encountered in a message to AWS Support.

Logs are saved in the following locations, based on your workstation's operating system:

  • Windows – C:/Users/<username>/.aws/snowball/logs/

  • Mac – /Users/<username>/.aws/snowball/logs/

  • Linux – /home/<username>/.aws/snowball/logs/

Logs are saved with the file name snowball_<year>_<month>_<date>_<hour>. The hour is based on local system time for the workstation and uses a 24-hour clock.

Example Log Name


Each log has a maximum file size of 5 MB. When a log reaches that size, a new file is generated, and the log is continued in the new file. If additional logs start within the same hour as the old log, then the name of the first log is appended with .1 and the second log is appended with .2, and so on.


Logs are saved in plaintext format and contain file name and path information for the files that you transfer. To protect this potentially sensitive information, we strongly suggest that you delete these logs once the job that the logs are associated with enters the completed status.

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