# Cloud Storage — Google Cloud Platform

Source: https://www.skillbyai.com/en/gcp/d-gcs

> Choose storage classes and locations, and secure buckets properly.

## Object storage with classes and locations

**Cloud Storage** stores objects in **buckets**. Each bucket has a **location type**: **region** (lowest latency to compute in that region), **dual-region** or **multi-region** (geo-redundant). **Storage classes** trade storage price against access price: **Standard** for hot data, **Nearline** (minimum storage duration 30 days), **Coldline** (90 days) and **Archive** (365 days). Unlike some other clouds' archive tiers, even Archive objects are readable **within milliseconds**; you simply pay more per read and an early-deletion charge. **Object Lifecycle Management** changes class or deletes objects by age; **Autoclass** can move objects automatically by access pattern. For security, enable **uniform bucket-level access** (IAM only, no per-object ACLs), keep **public access prevention** on, and share objects temporarily with **signed URLs**. Object versioning and retention policies protect against deletion.

## Classes by how often you read

The same API serves every class; only price and minimum duration change.

![Four stacked shelves from bright to faded, each holding identical box icons, with a clock symbol growing larger toward the bottom shelf.](assets/figures/gcp/section-5-map.svg) — Figure 5.1 — Standard, Nearline, Coldline and Archive storage classes.

## Lifecycle rules and a signed URL

Logs move to colder classes and are deleted after two years.

```bash
cat > lifecycle.json <<'EOF'
{
  "rule": [
    {"action": {"type": "SetStorageClass", "storageClass": "NEARLINE"},
     "condition": {"age": 30, "matchesPrefix": ["logs/"]}},
    {"action": {"type": "SetStorageClass", "storageClass": "ARCHIVE"},
     "condition": {"age": 180, "matchesPrefix": ["logs/"]}},
    {"action": {"type": "Delete"},
     "condition": {"age": 730, "matchesPrefix": ["logs/"]}}
  ]
}
EOF
gcloud storage buckets update gs://shop-dev-assets-123 --lifecycle-file=lifecycle.json

# a download link valid for 15 minutes (signed by impersonating a service account)
gcloud storage sign-url gs://shop-dev-assets-123/invoices/1001.pdf --duration=15m \
  --impersonate-service-account=signer@shop-dev-123456.iam.gserviceaccount.com
```

## Minimum durations are billed

Deleting a Coldline object after 10 days still bills 90 days of storage. Put data you rewrite often in Standard, even if it is read rarely.

**Quiz:** How quickly can you read an object stored in the Archive class?

- [x] Within milliseconds, at a higher per-read cost
- [ ] After a restore job that takes hours
- [ ] Only after copying it to Standard manually
- [ ] Never; Archive is write-only

*Answer:* Within milliseconds, at a higher per-read cost. All Cloud Storage classes offer millisecond access; colder classes cost more per read and have minimum durations.