Creating a Multipart Upload

You can create a multipart upload to store large objects in a bucket by dividing them into several smaller parts. A multipart upload can be in one of your buckets or one for which you have the appropriate permissions. You can then upload these parts concurrently, improving throughput for large objects on stable, high-bandwidth networks.

Recovery from network issues is thus quicker with a multipart upload, as each smaller part requires less data re-upload compared to a single large file.

Each part can range from 1 byte to 5 GiB. However, we recommend using multipart upload for objects of 100 MiB or more. Once all parts are uploaded, you can either complete the multipart upload (and reassemble the object in your bucket), or cancel it, removing all parts. This approach ensures efficient use of resources and bandwidth, allowing control over large data transfers. For more information, see Uploading a Part.

You can start uploading parts of an object without knowing its final size, which is useful for real-time object creation. Indeed, there is no time limit to complete the upload. You can pause and resume uploading parts as needed, which is ideal for ongoing projects or inconsistent network access.

You cannot modify the ACL or permissions of the multipart upload once it is created.

By default, the objects your store are private. However, you can grant access to the objects that you stored in your bucket with other users setting an Access Control List (ACL). For more information, see Access Control List (ACL) Reference.

Creating a Multipart Upload Using AWS CLI

Before you begin:

To create a multipart upload, use the create-multipart-upload command following this syntax:

Request sample
$ aws s3api create-multipart-upload \
    --profile YOUR_PROFILE \
    --bucket BUCKET \
    --acl private \
    --grant-full-control "id=USER_ID, id=USER_ID" \
    --grant-read "id=USER_ID, id=USER_ID" \
    --grant-read-acp "id=USER_ID, id=USER_ID" \
    --grant-write-acp "id=USER_ID, id=USER_ID" \

This command contains the following attributes that you need to specify:

  • (optional) profile: The named profile you want to use, created when configuring AWS CLI. For more information, see Installing and Configuring AWS CLI.

  • bucket: The bucket in which you want to create the multipart upload.

  • key: The name you want to give to the multipart upload.

    • When specifying new permissions, all the previous permissions are replaced. Therefore, you need to specify both the existing permissions that you want to keep (including for yourself) and the new permissions that you want to give in a single command.

    • If you are the owner of the bucket, you can lose your own permissions but not the ability to manage the ACL itself.

    For more information about existing permissions, see Getting Information About a Bucket ACL and Getting Information About an Object ACL.

  • (optional) acl: The ACL to apply to the multipart upload (private | public-read | public-read-write | authenticated-read | bucket-owner-read | bucket-owner-full-control).

  • (optional) grant-full-control: One or more IDs of users to whom you grant the full-control permission.

  • (optional) grant-read: One or more IDs of users to whom you grant the read permission.

  • (optional) grant-read-acp: One or more IDs of users to whom you grant the read-acp permission.

  • (optional) grant-write-acp: One or more IDs of users to whom you grant the write-acp permission.

  • endpoint: The endpoint corresponding to the Region you want to send the request to.

The create-multipart-upload command returns the following elements:

  • Bucket: The name of the bucket.

  • Key: The name of the multipart upload.

  • UploadId: The ID of the multipart upload.

    Save this element as it is mandatory for further commands.

Result Sample
    "Bucket": "BUCKET",
    "UploadId": "2~xrosnH8pbKTk3sjXijfGIUN1KAEM3Yc",

Related Pages

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