Data is stored in Amazon Glacier in "archives." An archive can be comprised of any data such as photos, videos, or documents. You can upload a single file as an archive or aggregate multiple files into a TAR or ZIP file and upload as one archive.
A single archive can be as large as 40 terabytes. You can store an unlimited number of archives and an unlimited amount of data in Amazon Glacier. Each archive is assigned a unique archive ID at the time of creation, and the content of the archive is immutable, meaning that after an archive is created it cannot be updated.