S3 Versioning

Overview

S3 Versioning keeps multiple variants of an object in the same bucket. Every time you upload a file with the same key (same name/path), instead of overwriting the previous file, S3 creates a new version. This is enabled at the bucket level and is considered a best practice.

Think of it like Git for your files — you can always go back to a previous version.

How Versioning Works

Upload: index.html → Version 1 (ID: null or auto-generated)
Upload: index.html → Version 2 (new version ID)
Upload: index.html → Version 3 (new version ID)

Bucket view (Show versions ON):
┌──────────────────────────────────────────┐
│ index.html  │ Version 3  │ abc123  │ ← current
│ index.html  │ Version 2  │ def456  │
│ index.html  │ Version 1  │ null    │ ← uploaded before versioning
│ coffee.jpg  │            │ null    │ ← uploaded before versioning
│ beach.jpg   │            │ null    │ ← uploaded before versioning
└──────────────────────────────────────────┘

When versioning is enabled:

• Each upload of the same key creates a new version with a unique version ID
• The latest version is served by default when someone requests the object
• All previous versions are retained and accessible

Why Use Versioning?

Important Notes

Delete Behavior — The Most Important Part

This is where versioning gets tricky and where exam questions focus. There are two completely different types of delete:

Type 1: Soft Delete (Delete Marker)

This happens when you delete an object without specifying a version ID (i.e., with "Show versions" toggle OFF in the console).

Before:
┌─────────────────────────────────┐
│ coffee.jpg  │ v1  │ null        │ ← visible
└─────────────────────────────────┘

After "Delete" (soft):
┌─────────────────────────────────┐
│ coffee.jpg  │ Delete Marker │ xyz789 │ ← hides the object
│ coffee.jpg  │ v1            │ null   │ ← still exists!
└─────────────────────────────────┘

Result: coffee.jpg appears deleted (404 Not Found)
        But v1 is still stored and can be restored!

• The object appears deleted to users (404 Not Found)
• But the actual data is still stored behind the delete marker
• The console shows "delete" (not "permanently delete") as the confirmation text
• Reversible — delete the delete marker to restore the object

Type 2: Permanent Delete (Specific Version)

This happens when you delete a specific version ID (i.e., with "Show versions" toggle ON in the console).

Before:
┌─────────────────────────────────┐
│ index.html  │ v3  │ abc123      │ ← current
│ index.html  │ v2  │ def456      │
│ index.html  │ v1  │ null        │
└─────────────────────────────────┘

After permanently deleting v3 (abc123):
┌─────────────────────────────────┐
│ index.html  │ v2  │ def456      │ ← now current
│ index.html  │ v1  │ null        │
└─────────────────────────────────┘

Result: v3 is GONE FOREVER. v2 becomes the current version.

• The specific version is permanently destroyed — cannot be recovered
• The console shows "permanently delete" as the confirmation text
• Irreversible — this is a destructive operation

Restoring a Soft-Deleted Object

To restore an object that was soft-deleted (has a delete marker):

Step 1: Enable "Show versions" toggle
Step 2: Find the Delete Marker for the object
Step 3: Select the Delete Marker → Delete it
Step 4: Confirm "permanently delete" (you're deleting the marker, not the object)
Step 5: The previous version is now restored and visible again

Hands-On Walkthrough

Enabling Versioning

1. Go to bucket Properties → Bucket Versioning → Edit → Enable
2. Save changes
3. From now on, any file you upload will get a version ID

Uploading a New Version

1. Edit your index.html locally (e.g., change "I love coffee" to "I REALLY love coffee")
2. Upload the modified index.html to the bucket
3. Visit your website URL → see the updated content
4. In the console, click Show versions toggle
5. You'll see two versions of index.html:
   • One with version ID null (uploaded before versioning)
   • One with a real version ID (uploaded after versioning)

Rolling Back

1. With "Show versions" ON, select the latest version of index.html
2. Delete it (this is a permanent delete of that specific version)
3. The previous version becomes current
4. Refresh your website → see the old content ("I love coffee")

Soft Delete and Restore

1. Turn "Show versions" OFF
2. Select coffee.jpg → Delete → type "delete" → confirm
3. The file appears gone from the bucket
4. Turn "Show versions" ON → you'll see a Delete Marker on coffee.jpg
5. The original coffee.jpg (version null) is still there behind the marker
6. Select the Delete Marker → Delete it → type "permanently delete"
7. The coffee.jpg is restored and visible again

Questions & Answers