Introduction: To keep past iterations of an object automatically, you can enable Blob storage versioning. If a blob is edited or removed, you can access prior versions of the blob by turning on blob versioning. Blob versioning is part of a comprehensive data protection strategy for blob data
Blob Versioning: Configuration/Setting at the scope of storage-account level
One can enable Blob storage versioning to automatically maintain previous versions of an object. When blob versioning is enabled, you can access earlier versions of a blob to recover your data if it is modified or deleted.
- When this feature is enabled, azure storage automatically creates a new version with unique version-ID (the value of version-ID is the timestamp when the blob was last modified)
- A version captures the state of a blob at a given point in time. Each version is identified with the above mentioned unique version-ID
- A version ID can identify the current version or a previous version. A blob can have only one current-version* at a time
- If the write operation creates a new blob, then the resulting blob is the current version of the blob.
- If the write operation modifies an existing blob, then the current version becomes a previous version and updated one is the newest version.
- Blob versions are immutable. You cannot modify the content or metadata of an existing blob version
- Microsoft recommends maintaining fewer than 1000 versions per blob otherwise latency for blob listing operations can increase
- Blob versioning cannot help you to recover from the accidental deletion of a storage account or container
- You can perform read or delete operations on a specific version of a blob by providing its version ID, otherwise operation acts on the current version
- The version ID remains the same for the lifetime of the version
- When blob versioning is turned on, each write operation to a blob creates a new version
- A blob that was created prior to versioning being enabled for the storage account does not have a version ID
- Disabling blob versioning does not delete existing blobs, versions, or snapshots (and then the blob modified /created doesn’t have a version ID)
- If versioning and soft delete are both enabled for a storage account, then when you delete a blob, the current version of the blob becomes a previous version
- Blob versioning is available for standard general-purpose v2, premium block blob, and legacy Blob storage accounts
- Storage accounts with a hierarchical namespace enabled for use with Azure Data Lake Storage Gen2 are not currently supported
- Enabling blob versioning can result in additional data storage charges to your account
