What is Amazon Glacier?
Introduction to Amazon Glacier
- Amazon Glacier is another cloud storage service related to Amazon S3, but optimized for data archiving and long-term backup at extremely low cost optimized for infrequently used data suitable for “cold data,” which is data that is rarely accessed and retrieved for which a nominal time of three to five hours is acceptable.
- Amazon Glacier is an extremely low-cost storage service that provides durable storage with security features for data archiving and backup which can cost effectively store data for months, years, or even decades.
- With the help of Amazon Glacier you can also enable to offload the administrative burdens of operating and scaling storage to AWS so that you don’t have to worry about capacity planning, time-consuming hardware migrations, hardware provisioning, replicated data, hardware failure detection and recovery.
Amazon Glacier Data Model
Amazon Glacier is a REST-based web service whose data model includes vaults and archives as the core resources. In addition to this the Amazon Glacier data model also includes job and notification-configuration resources. These resources complement the core resources.
When you create a vault (a vault is a container for storing archives), you have to specify a name and select an AWS region where you want to create the vault.
Each vault resource has a unique address. The general form is:
Suppose for example, if you want to create a vault (example vault) in the US West (Oregon) Region then the vault can then be addressed by the following URI:
Depending on your application or business needs, you can store these archives in one vault (you can store an unlimited number of archives in a vault) or multiple vaults.
An archive is a base unit of storage in Amazon Glacier which can be a photo, video or document or any data. Each archive has a unique ID (Amazon Glacier assigns the archive an ID, which is unique in the AWS region in which it is stored) and an optional description. [Please Note that you can only specify the optional description during the upload of an archive]
Each archive has a unique address. The general form is:
The quoted URI is an example of an archive stored in the vault (example vault) in the region of US West (Oregon):
In Amazon Glacier retrieving an archive and vault inventory (list of archives) are asynchronous operations (first initiate a job and then download the job output after Amazon Glacier completes the job). The data retrieval requests are queued and most of the jobs take about four hours to complete.
You have to provide a vault name to initiate a vault inventory job. While the archive retrieval job requires both the vault name (where the archive resides) and the archive ID you prefer to download. When you initiate these jobs you can also provide an optional job description. These descriptions can help you in identifying.
When a job request (initiate a job) is send, Amazon Glacier returns a job ID to track the job. Both the inventory jobs vault (a vault can have multiple jobs in progress at any point in time) and archive retrieval job is uniquely identified by a URI which can be of the following form:
Below is an example of a job associated with a vault (example vault)
Amazon Glacier maintains crucial information like job type, description, status, creation and completion date for each and every job.
Once Amazon Glacier completes a job, then you can download the job output.
- Notification Configuration:-
Since jobs take time to complete, Amazon Glacier supports a notification mechanism to notify you when a job is complete. You can also configure a vault to send notification to an Amazon SNS (Simple Notification Service) topic when jobs complete and can specify one SNS topic per vault in the notification configuration.
The following is an example of vault notification configuration:
Amazon Glacier supports different operations to set, get, and delete a notification configuration. No notifications are sent (when any data retrieval operation on the vault is complete) when you delete a notification configuration. The notification configuration is stored as a JSON document.
Supported Operations in Amazon Glacier
The following supported operations are asynchronous:
- Retrieving an archive.
- Retrieving a vault inventory (list of archives).
- Vault Operations:-Amazon Glacier provides operations to create and delete vaults. You can obtain a vault description (vault description provides information such as creation date, number of archives in the vault, total size in bytes used by all the archives in the vault, and the date Amazon Glacier generated the vault inventory) for a specific vault or for all vaults in a region.
- Archive Operations:-Amazon Glacier provides operations for you to upload and delete archives. To update an existing archive first you must have to delete the existing archive and upload a new archive. [Please Note that each time you upload an archive, Amazon Glacier generates a new archive ID]
- Job:-Retrieving an archive or vault inventory from Amazon Glacier is an asynchronous operation (It requires you to first initiate a job, wait for the job to complete and then download the job output). Amazon Glacier provides operations for you to initiate a job, get job description, and retrieve a list of jobs associated with a vault; it can also post a message to an Amazon SNS (Simple Notification Service) topic upon job completion. [Please Note that most jobs take about four hours to complete]