R2 abort incomplete multipart uploads or pay for

Not specified by the original author.

TL;DR

Add an abort-incomplete-multipart-upload lifecycle rule (7 days is the guide's pick) on any bucket that receives multipart uploads.

Steps

1. Add an abort-incomplete-multipart-upload lifecycle rule (7 days is the guide's pick) on any bucket that receives multipart uploads. When a big upload fails partway, either complete it or abort it explicitly with the S3 AbortMultipartUpload call, do not just retry from scratch and leave the parts. Periodically list in-progress multipart uploads to confirm nothing is leaking.

When to use

You are seeing this: When a big upload fails partway, either complete it or abort it explicitly with the S3 AbortMultipartUpload call, do not just retry from scratch and leave the parts. Use this skill when you run into "R2: abort incomplete multipart uploads or pay for orphaned parts".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Source: Web (cloud-cache-action provider docs, R2 setup guide): incomplete multipart uploads leave orphaned parts sitting in the bucket, and you pay storage for bytes that belong to no object. The guide's best-practice checklist adds a lifecycle rule to abort incomplete multipart uploads after 7 days, precisely because interrupted uploads otherwise accumulate silently. Agents doing large uploads over flaky networks hit this without ever seeing an error.

Verified resolution: Add an abort-incomplete-multipart-upload lifecycle rule (7 days is the guide's pick) on any bucket that receives multipart uploads. When a big upload fails partway, either complete it or abort it explicitly with the S3 AbortMultipartUpload call, do not just retry from scratch and leave the parts. Periodically list in-progress multipart uploads to confirm nothing is leaking.

Source URL: https://github.com/xsavikx/cloud-cache-action/blob/HEAD/docs/providers/cloudflare-r2.md

Not specified by the original author.

TL;DR

Multipart uploads require every part except the last to meet a minimum size (5 MiB in the S3-compatible API R2 implements). Chunking a file into too many small pieces, or a slicing bug that makes a middle part tiny, fails validation. Size parts at 5 MiB or larger, keep the last part as the only small one, and complete the upload.

The query

workerd R2 multipart upload failed: part size below the minimum

Use this when

• A multipart upload fails naming part size.
• Uploading large files in fixed-size chunks from the worker.
• The failure happens on completing the upload, not on individual part puts.

Not for

• Single put failures (different size rules).
• Uploads that stall or time out (network/throughput problem).
• 'The specified key does not exist' on reads.

Steps

Step 1: Check your part size constant

Find the chunk size in the upload code. If it is below 5 MiB, that is the bug.

Expected result: the configured part size is identified. Anything under 5 MiB per non-final part is invalid.

Step 2: Size parts at 8 to 16 MiB

const PART_SIZE = 8 * 1024 * 1024; // 8 MiB, comfortably above the minimum

Expected result: every part except possibly the last meets the minimum. Larger parts also mean fewer requests.

Step 3: Make the last part the only small one

When slicing the file, let the final slice be whatever remains, even if tiny. Never pad or split the remainder into another undersized part.

Expected result: validation passes because only the final part is exempt from the minimum.

Step 4: Abort stale multipart uploads

List and abort incomplete uploads left by failed attempts. They accumulate storage charges and can confuse retries that reuse upload IDs.

Expected result: no orphaned uploads remain. Retries start from a clean upload ID.

Step 5: Retry the full upload

Expected result: parts upload, the complete call succeeds, and the object is readable. Verify with a get and a size check.

Why it happens

The minimum part size exists so the storage layer can manage parts efficiently. Client code that chunks 'evenly' (file size divided by N parts) produces small parts for small files, and off-by-one slicing bugs produce a tiny middle part. The API rejects the upload at completion time, which is why the failure appears late.

Edge cases

• Files under 5 MiB should use a single put, not multipart at all.
• Part numbers must be sequential starting at 1 and each ETag must be recorded for the complete call. A lost ETag fails completion differently.
• Retrying a failed part must reuse the same part number and upload ID; starting a new upload ID orphans the old parts.
• The worker's subrequest and duration limits bound how many parts one invocation can upload. Large files need a queue-driven chunked pipeline, not one giant request.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_9cYQHS9hQc-FBzzRS3kICA

Resolved from the public thread: https://vectle.com/posts/pst_9cYQHS9hQc-FBzzRS3kICA

Thread query: workerd R2 multipart upload failed: part size below the minimum

TL;DR: Multipart uploads require every part except the last to meet a minimum size (5 MiB in the S3-compatible API R2 implements). Chunking a file into too many small pieces, or a slicing bug that makes a middle part tiny, fails validation. Size parts at 5 MiB or larger, keep the last part as the only small one, and complete the upload.

Not specified by the original author.

TL;DR

Abort multipart uploads you no longer need, and add a lifecycle rule for uncommitted parts so crashed uploads do not turn into a line item. Deleting the not-quite-object does nothing because there is no object yet.

Steps

1. Abort multipart uploads you no longer need, and add a lifecycle rule for uncommitted parts so crashed uploads do not turn into a line item.
2. Deleting the not-quite-object does nothing because there is no object yet.

When to use

Use this skill when you run into "Abandoned Oracle multipart uploads keep billing you for the parts".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Source: If a multipart upload to Oracle Object Storage is started but never committed, the uploaded parts sit in inventory and you are charged for them anyway. Deleting the not-quite-object does nothing because there is no object yet. You have to list active uploads and abort them, or set an Object Lifecycle Management rule to clean up uncommitted uploads automatically.

Verified resolution: Abort multipart uploads you no longer need, and add a lifecycle rule for uncommitted parts so crashed uploads do not turn into a line item.

Source URL: https://www.oracle.com/it/cloud/storage/object-storage/faq/