Hedronite · Cert Lesson · Cert-Prep / Google · Sun 2026-09-13

GCP PCA: Cloud Storage classes, lifecycle, retention versus versioning — three shelves

Three controls on one bucket. The exam will offer you one word for all three.

Lesson Class: Cert-Prep (GCP PCA)
Cloud Referent: Cloud Storage classes + lifecycle + retention/versioning
Paired Ops: Python GCS lifecycle and retention census
Paired Dev: Python google-cloud-storage inventory
Paired Go: Go BucketAttrs inventory
Grounding: Ch.3 lifecycle JSON · PCA-Notes · ACE/PCA cheatsheet
Class
Standard → Archive cost curve.
Lifecycle
Age rules move or delete.
Retention
Lock is not versioning.
Name the shelf before you pick the feature.

Three controls on one bucket. The exam will offer you one word for all three.

§I — Frame: fourth PCA visit, object door

08-08 opened the hierarchy. 08-20 opened Compute. 09-01 opened BigQuery prune. Counter 10 mod 4 returns seat 2: GCP PCA. The leftover is object storage policy.

Cheatsheet classes: Standard, Nearline, Coldline, Archive. Retrieval cost rises as access frequency falls. Bucket names are globally unique. Know gcloud storage (and legacy gsutil) as the CLI surface.

§II — Lifecycle

Chapter-3 ships the rule shape you will meet in labs and scenarios:

ActionCondition (example)
SetStorageClass → COLDLINEage 30; matches STANDARD or NEARLINE
Deleteage 365

Lifecycle answers cost and cleanup. It does not answer legal hold. A Delete rule that fires inside a compliance window is an architecture defect, even when the JSON is valid.

§III — Retention versus versioning

PCA-Notes:

ControlProtectsAllows
Retention policyDeletion and changes for a period; lock makes period immutableOverwrite only when policy permits
Object versioningHistory of generationsModification via new generations

GCS objects are immutable at a generation. Overwrite creates a new generation when versioning is on. Retention locked means you cannot shorten the period to escape a delete need. The exam loves the swap: candidate picks versioning when the stem asked for undelete protection under retention, or picks retention when the stem asked for prior-generation recovery.

§IV — Worked scenario

A media archive must stay recoverable for one year, cold after 30 days, and must not be deleted by operators for seven years.

  1. Default or lifecycle path into Coldline/Archive after 30 days (Chapter-3 pattern).
  2. Retention period ≥ seven years; lock when policy is final.
  3. Versioning optional for overwrite history; add noncurrent delete rules if cost matters.
  4. Reject "only versioning" as the seven-year delete shield.

§V — Exam traps

  1. Treating Nearline as free storage with no retrieval cost.
  2. Using lifecycle Delete as a compliance lock.
  3. Assuming retention unlocks on demand after lock.
  4. Confusing bucket default class with object class after lifecycle moves.
  5. Designing Org Policy / Shared VPC answers on a storage-class stem (leave 08-08 on its shelf).

§VI — Closing

Name the shelf before you pick the product feature. Ops and Dev inventory the live fields; this seat grades the choice.

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