Cloud Storage

Cloud Storage is GCP's object storage service for storing and accessing any amount of data. It's designed for durability, availability, and scalability. Use it for everything from website assets and backups to data lakes and machine learning training data.

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Key Concepts

Buckets

A bucket is a container for your data. Every object in Cloud Storage belongs to a bucket.

• Bucket names must be globally unique across all of GCP
• A bucket has a location (region, dual-region, or multi-region)
• A bucket has a default storage class
• You can set access controls at the bucket or object level

Objects

An object is a file stored in a bucket, along with its metadata:

• Objects have no size limit (up to 5 TB per object)
• Objects are immutable — you replace the entire object to update it
• Each object has a unique key (name) within its bucket

gs://my-app-assets/images/logo.png
  |         |              |
  bucket    folder         object key

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Storage Classes

Cloud Storage offers four storage classes with different cost and access characteristics:

Storage Class	Access Frequency	Min Storage Duration	Use Case
Standard	Frequently accessed	None	Hot data, websites, streaming
Nearline	Once per month	30 days	Backups, infrequently accessed data
Coldline	Once per quarter	90 days	Disaster recovery, archival
Archive	Once per year	365 days	Long-term archival, compliance

Key point: All storage classes provide the same durability (99.999999999% — eleven 9s), latency, and API. The only differences are cost structure and minimum storage duration.

Cost Trade-off

As you move from Standard to Archive:

• Storage cost decreases (cheaper to store data)
• Access cost increases (more expensive to read data)

Choose the class that matches your access pattern.

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Bucket Locations

Location Type	Description	Use Case
Region	Single region (e.g., europe-west2)	Data close to compute resources
Dual-region	Pair of regions (e.g., EUR4 = europe-north1 + europe-west4)	Higher availability within a continent
Multi-region	Large geographic area (e.g., EU, US, ASIA)	Highest availability, global access

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Object Versioning

When versioning is enabled on a bucket:

• Every change to an object creates a new version
• Deleted objects are retained as non-current versions
• You can restore previous versions of an object
• Older versions incur storage charges

# Enable versioning
gsutil versioning set on gs://my-bucket

# List all versions
gsutil ls -la gs://my-bucket/file.txt

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Object Lifecycle Management

Lifecycle rules automatically manage objects based on conditions: