AWS users can realize cost benefits by performing a simple transition between S3 storage classes. The transition can only be done using “lifecycle configuration rules” which are fully automated. Before you start transitioning S3 storage classes, here is what you need to know:
S3 Infrequent Access:
- The transition to S3 Infrequent Access (IA) usually occurs immediately.
- Cost benefits of transitioning to STANDARD_IA can be realized for larger objects. Amazon S3 does not transition objects less than 128 Kilobytes in size to the STANDARD_IA storage class. For smaller objects it is not cost effective and Amazon S3 will not transition them.
- Objects must be stored at least 30 days in the current storage class before you can transition them to STANDARD_IA. For example, you cannot create a lifecycle rule to transition objects to the STANDARD_IA storage class one day after creation.
- Transitions before the first 30 days are not supported because newer objects are often accessed more frequently or deleted sooner than is suitable for STANDARD_IA.
- If you are transitioning noncurrent objects (versioned bucket scenario), you can transition to STANDARD_IA only objects that are at least 30 days noncurrent.
S3 Glacier:
- Transition time from S3 Standard to S3 Glacier takes around 1 day.
- Objects in the GLACIER storage class are not available in real time.
- Usually most cost-effective option for storing archived infrequently accessed data.
- Archived objects are Amazon S3 objects, but before you can access an archived object, you must first restore a temporary copy of it. The restored object copy is available only for the duration you specify in the restore request. After that, Amazon S3 deletes the temporary copy, and the object remains archived in Amazon Glacier.
- Note that object restoration from an archive can take up to five hours.
- You can restore an object by using the Amazon S3 console or programmatically by using the AWS SDKs wrapper libraries or the Amazon S3 REST API in your code. For more information, see POST Object restore.
- The transition of objects to the GLACIER storage class is one-way.
- You cannot use a lifecycle configuration rule to convert the storage class of an object from GLACIER to STANDARD or REDUCED_REDUNDANCY. If you want to change the storage class of an already archived object to either STANDARD or REDUCED_REDUNDANCY, you must use the restore operation to make a temporary copy first. Then use the copy operation to overwrite the object as a STANDARD, STANDARD_IA, or REDUCED_REDUNDANCY object.
- The GLACIER storage class objects are visible and available only through Amazon S3, not through Amazon Glacier.
- Amazon S3 stores the archived objects in Amazon Glacier. However, these are Amazon S3 objects, and you can access them only by using the Amazon S3 console or the Amazon S3 API. You cannot access the archived objects through the Amazon Glacier console or the Amazon Glacier API.
Transitions that are not supported:
- You can’t transition from STANDARD_IA storage class to the STANDARD or REDUCED_REDUNDANCY classes.
- You can’t transition from GLACIER to any other storage class.
- You can’t transition from any storage class to REDUCED_REDUNDANCY.