An AWS customer wanted to scale their machine learning (ML) workload to hundreds of thousands of machine instances. Their goal was to download large images, including people and cars, from S3 to EBS storage to process for training a self-driving car. Optimizing and scaling storage usage was key, but a bottleneck was created when writing the images to disc. The AWS team profiled the application using Altair Mistral™ to see how the workflow could be improved, with results that were well worth the effort.