PDE Storing the Data Practice Question
A healthcare company stores patient documents in a Cloud Storage bucket with a retention policy. Auditors require that once an object is written, it cannot be overwritten or deleted by any user, including project owners, for 7 years. The company also wants to minimize storage cost after the first year while preserving immutability. What should the data engineer configure?
⚠ Common exam trap
It's easy for candidates to confuse permission-based deletion prevention, such as IAM deny policies, with a locked retention policy that enforces WORM even against project owners.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Apply a bucket lock on a retention policy with a 7-year retention period, then add a lifecycle rule to transition objects to Archive after 365 days.
A locked retention policy is the only Cloud Storage mechanism that enforces immutability against all users, including project owners, for the specified duration. Combining it with a lifecycle rule that transitions objects to Archive after one year satisfies the retention requirement while lowering storage cost for the remaining six years.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Enable uniform bucket-level access and create a retention policy without locking it, then transition objects to Coldline after 365 days.
Why it's wrong here
An unlocked retention policy can be removed or shortened by a user with the storage.buckets.update permission, so objects are not truly immutable. Uniform bucket-level access only changes how permissions are evaluated, not object retention. Coldline transition reduces cost but does not enforce the seven-year WORM guarantee required by auditors.
- ✓
Apply a bucket lock on a retention policy with a 7-year retention period, then add a lifecycle rule to transition objects to Archive after 365 days.
Why this is correct
A locked retention policy enforces WORM semantics: objects cannot be deleted or overwritten until the retention period expires, and even project owners cannot remove the lock. A lifecycle rule can still transition the storage class to Archive after one year, reducing cost while the retention policy continues to protect the data for the full seven years.
- ✗
Set an IAM deny policy on storage.objects.delete for all principals and use a lifecycle rule to move objects to Nearline after 365 days.
Why it's wrong here
IAM deny policies can restrict deletion, but they are permission-based and can be changed by an administrator with the right role, so they do not provide the immutable, owner-proof guarantee auditors require. Nearline also has a 30-day minimum storage duration, which is acceptable but does not address immutability. This does not meet the WORM requirement.
- ✗
Enable Object Versioning and set a lifecycle rule to move objects to Coldline after 365 days.
Why it's wrong here
Object Versioning retains noncurrent versions but does not prevent deletion or overwrite of the live object; a user with storage.objects.delete permission can still remove data. A lifecycle rule to Coldline changes the storage class but does not enforce immutability. This configuration fails the auditor requirement that no user, including owners, can alter or delete objects.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Google Cloud exam blueprint
This PDE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PDE exam.