15 documented AWS S3 cost inefficiencies, each with how to detect it and how to fix it.
AWS S3CER-0334
Amazon S3 bills for nearly every API request - LIST, HEAD, GET, PUT, COPY, and POST - independently of storage charges (DELETE and CANCEL requests are free). Workloads originally designed for locally-provisioned storage, where listing a...
AWS S3CER-0330
Machine learning experimentation workflows - particularly those managed through experiment tracking platforms - generate large volumes of artifacts in object storage. Every training run produces model checkpoints, evaluation outputs,...
AWS S3CER-0307
Organizations often use the Standard - Infrequent Access (Standard-IA) storage class based on documentation and code that predate 2021 updates to the Intelligent Tiering storage class. Intelligent Tiering became suitable as an initial S3...
AWS S3CER-0303
When external Delta tables are dropped from Databricks Unity Catalog or the legacy Hive metastore, only the table metadata is removed - the underlying data files in cloud object storage (such as S3, ADLS, or GCS) remain untouched and...
AWS S3CER-0237
When S3 versioning is enabled but no lifecycle rules are defined for non-current objects, outdated versions accumulate indefinitely. These non-current versions are rarely accessed but continue to incur storage charges. Over time, this...
AWS S3CER-0229
S3 buckets configured with SSE-KMS but without Bucket Keys generate a separate KMS request for each object operation. This behavior results in disproportionately high KMS request costs for data-intensive workloads such as analytics,...
AWS S3CER-0200
S3 Storage Lens Advanced provides valuable insights into storage usage and trends, but it incurs a recurring cost. Organisations often enable it during an optimization initiative but fail to turn it off afterwards. When no active storage...
AWS S3CER-0160
While moving objects to colder storage classes like Glacier or Infrequent Access (IA) can reduce storage costs, premature transitions without analyzing historical access patterns can lead to unintended expenses. Retrieval charges, restore...
AWS S3CER-0054
When large numbers of objects are deleted from S3 - such as during scripted cleanups or batch jobs that call DeleteObject or DeleteObjects-CloudTrail can log every individual delete operation if data event logging is enabled. This is...
AWS S3CER-0161
When EC2 instances in private subnets access Amazon S3 in the same region without a Gateway VPC Endpoint, traffic is routed through a NAT Gateway to the public S3 endpoint. Data transfer from S3 to EC2 in the same region is free, but every...
AWS S3CER-0076
Multipart upload allows large files to be uploaded in segments. Each part is stored individually until the upload is finalized by a "CompleteMultipartUpload" request. If this final request is never issued-due to a timeout, crash, failed...
AWS S3CER-0037
S3 buckets often persist after projects complete or when the associated workloads have been retired. If a bucket is no longer being read from or written to - and its contents are not required for compliance, backup, or retention...
AWS S3CER-0032
Some S3 lifecycle policies are configured to transition objects from Standard storage to Intelligent-Tiering after a fixed number of days (e.g., 30 days). This creates a delay where objects reside in S3 Standard, incurring higher storage...
AWS S3CER-0070
S3 Standard is the default storage class and is often used by default even for data that is rarely accessed. Keeping large volumes of infrequently accessed data in S3 Standard leads to unnecessary costs. Data such as backups, logs,...
AWS S3CER-0397
Archiving to S3 Glacier Flexible Retrieval or S3 Glacier Deep Archive only saves money when the per-GB storage discount outweighs the fixed per-object costs of getting there. Every object transitioned by a lifecycle rule is a billable...
