Amazon Glacier is an extremely low cost cloud based storage service

provided by Amazon.

We mainly use Amazon Glacier for long-term backup purpose.

Amazon Glacier can be used for storing data archives for months, years or

even decades.

It can also be used for long term immutable storage based on regulatory and

archiving requirements. It provides Vault Lock support for this purpose. In this

option, we write once but can read many times same data.

One use case is for storing certificates that can be issued only once and only

the original person keeps the main copy

https://www.techtarget.com/searchaws/definition/Glacier-Amazon-Glacier#:~:text=Amazon%20Glacier%2C%20also%20known%20as,and%20backup%20of%20cold%20data.