AWS Glacier, also known as Amazon Glacier, is a low-cost, durable, and secure cloud storage service provided by Amazon Web Services. It is designed for long-term storage of data that is infrequently accessed and where retrieval times can be in hours.

Here are some key features and characteristics of AWS Glacier:

1. Low-Cost Storage: Glacier is optimized for long-term storage at a low cost. The pricing is significantly lower than other AWS storage services, such as Amazon S3. However, retrieval costs and times should be considered for accessing the data.

2. Durability and Data Protection: Glacier is designed to provide high durability for data storage. It automatically stores data across multiple facilities within an AWS Region to protect against data loss.

3. Archive and Retention Policies: With Glacier, you can create archives, which are units of data stored in Glacier. You can define retention policies to control how long the data is retained, ensuring compliance with regulatory requirements.

4. Vault and Inventory Management: Glacier organizes data into “vaults,” which act as containers for storing archives. You can create, manage, and configure vaults using the Glacier API or the AWS Management Console. Glacier also provides inventory management, allowing you to list the archives within a vault.

5. Data Retrieval: Glacier offers different retrieval options, each with its own cost and retrieval time. Standard retrievals typically take a few hours, while expedited retrievals can provide faster access but at a higher cost. Bulk retrievals offer the lowest cost but with longer retrieval times.

6. Security and Compliance: Glacier provides security features such as server-side encryption and integration with AWS Identity and Access Management (IAM) for access control. It also supports compliance requirements, including data sovereignty and regulatory standards like GDPR and HIPAA.

AWS Glacier is commonly used for archival purposes, backup and disaster recovery, long-term data retention, and compliance storage. It is a cost-effective solution for organizations that need to store large volumes of data for extended periods without requiring immediate access to the data.