MinIO InvalidPartSize error encountered during multipart upload.

What is MinIO InvalidPartSize error encountered during multipart upload.

Understanding MinIO and Its Purpose

MinIO is a high-performance, distributed object storage system designed to handle unstructured data such as photos, videos, log files, backups, and container images. It is compatible with Amazon S3 cloud storage service and is ideal for large-scale data infrastructures. MinIO is widely used for its simplicity, scalability, and high availability.

Identifying the Symptom: InvalidPartSize Error

When using MinIO for multipart uploads, you might encounter an InvalidPartSize error. This error typically arises during the upload process, indicating that one or more parts of the file being uploaded do not meet the required size constraints.

What You Observe

During a multipart upload, you may receive an error message similar to:

InvalidPartSize: The size of one or more parts in the multipart upload is invalid.

This error halts the upload process, preventing the file from being stored in the MinIO bucket.

Explaining the InvalidPartSize Issue

The InvalidPartSize error is triggered when the size of any part in a multipart upload is less than the minimum required size. In MinIO, each part of a multipart upload must be at least 5 MB in size, except for the last part, which can be smaller if necessary.

Why This Happens

This issue often occurs when the application or script handling the upload does not correctly segment the file into appropriately sized parts, or when there is a misunderstanding of the multipart upload requirements.

Steps to Fix the InvalidPartSize Issue

To resolve the InvalidPartSize error, follow these steps:

Step 1: Review Your Upload Logic

Ensure that your application or script is correctly dividing the file into parts that are at least 5 MB in size. If you are using a library or SDK, check its documentation to confirm it supports MinIO's multipart upload requirements.

Step 2: Adjust Part Size Configuration

If you are manually configuring the part sizes, make sure each part is at least 5 MB. For example, in a Python script using the Boto3 library, you can specify the part size as follows:

import boto3s3_client = boto3.client('s3')# Set part size to 5 MBconfig = boto3.s3.transfer.TransferConfig(multipart_chunksize=5 * 1024 * 1024)s3_client.upload_file('largefile.txt', 'mybucket', 'largefile.txt', Config=config)

Step 3: Verify the Last Part

Ensure that the last part of the upload can be smaller than 5 MB if it is the remaining portion of the file. This is acceptable and will not trigger the InvalidPartSize error.

Additional Resources

For more information on multipart uploads and MinIO, consider visiting the following resources:

MinIO Client Complete Guide Amazon S3 Multipart Upload Overview

By following these steps and ensuring compliance with the multipart upload requirements, you can effectively resolve the InvalidPartSize error and ensure successful uploads to your MinIO storage.