CargoShip

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Analyzing existing S3 spend ​

cargoship analyze scans an S3 bucket you already have, calculates what it costs today, and estimates how much re-archiving it in CargoShip's chunked, compressed format could save. It works against AWS S3 and S3-compatible providers (Wasabi, Backblaze B2, MinIO). The full flag list lives in the command reference.

bash
cargoship analyze s3://BUCKET[/PREFIX]

Basic analysis ​

bash
cargoship analyze s3://my-bucket
cargoship analyze s3://my-bucket/data

CargoShip walks the bucket, tallies object counts, sizes, and storage-class distribution, computes the current monthly cost, and projects the cost after re-archiving:

═══════════════════════════════════════════════════════════
📊 S3 COST ANALYSIS
═══════════════════════════════════════════════════════════

Bucket: s3://my-bucket
Region: us-west-2

📦 Bucket Statistics:
   Total Objects:        1,284,905
   Total Size:           4.7 TB
   Average Object Size:  3.8 MB

📏 Size Distribution:
   Small (<1 MB):        902,110
   Medium (1-100 MB):    378,220
   Large (100MB-1GB):    4,401
   Huge (>1 GB):         174

═══════════════════════════════════════════════════════════
💰 CURRENT MONTHLY COSTS
═══════════════════════════════════════════════════════════
   Storage Cost:         $110.79
   Request Costs:        $6.42  (estimated)

═══════════════════════════════════════════════════════════
🎯 CARGOSHIP SAVINGS POTENTIAL
═══════════════════════════════════════════════════════════
📦 After CargoShip Re-archiving (Estimated):
├─ Chunks:                18,300 (from 1,284,905 objects)
├─ Total Size:            2.9 TB (compressed)
└─ Projected Monthly Cost: $71.04

The savings comparison is shown by default; pass --show-savings=false to suppress it and see only the current-cost breakdown.

Sampling large buckets ​

Scanning millions of objects is slow. --sampling estimates the totals from a subset instead of listing every object; tune the sample with --sample-size (default 10,000):

bash
cargoship analyze s3://my-bucket --sampling
cargoship analyze s3://my-bucket --sampling --sample-size 50000

Sampled runs label their figures as estimates and note the sample size. Use a full scan for billing-grade numbers and sampling for a quick order-of-magnitude read on a huge bucket.

Non-AWS providers ​

Point analyze at an S3-compatible provider with --provider plus --endpoint-url:

bash
# Wasabi
cargoship analyze s3://my-bucket --provider wasabi \
  --endpoint-url https://s3.wasabisys.com

# Backblaze B2
cargoship analyze s3://my-bucket --provider b2 \
  --endpoint-url https://s3.us-west-002.backblazeb2.com

# MinIO (self-hosted)
cargoship analyze s3://my-bucket --provider minio \
  --endpoint-url https://minio.example.com

Supported --provider values are aws (default), wasabi, b2, minio, and custom. Each applies that provider's pricing model to the cost estimate.

Scripting ​

Emit machine-readable output with --format json and disable the live scan progress with --progress=false (handy in CI logs):

bash
cargoship analyze s3://my-bucket --format json --progress=false

Other flags: --region (auto-detected from the bucket if omitted) and --profile to select an AWS credentials profile.

Best practices ​

TIP

  • Start with --sampling on huge buckets to get a fast estimate, then run a full scan on the ones worth migrating.
  • Analyze before you migrate — the projected cost tells you whether re-archiving a bucket is worth the effort.
  • Use --format json to track spend over time or feed a dashboard.
  • Set --provider/--endpoint-url for non-AWS storage so the pricing model matches your actual bill.

See also ​