Stratus object storage system

Created by Unknown User (bjsmith), last modified on 2023-04-25

Stratus, the CISL object storage disk system described here, is for long-term data storage.

Some documents attached below include the name of the vendor – Active Scale, a division of Western Digital – and some refer to the system with the name "Data Commons S3."

Page contents

System overview

Stratus does NOT have POSIX file system access. In fact, it differs from other file systems in many ways:

  • There is no directory structure, only a flat hierarchy with a single level (bucket and content of the bucket).
  • The data and metadata are accessed programmatically (rather than at the command line) with get/put commands, via an HTTP REST API.
  • Data and metadata can be accessed either via a library (such as Python's boto3) or a web browser (either directly for the HTTP calls or via web interface).
  • The system uses an API that is similar but not identical to the Amazon Web Services S3.
  • Accounts are identified by a key pair: access key and secret key, as in these examples:
    • Access key: AK0IYXKCCIA63BMNCOUN
    • Secret key: Joeke2uHHebQdKJBgTVUzp+j7uRDthPdIBl5YaLE
  • Accounts are associated with email, and each email address can have only a single account with a single role. A person who needs two roles must use two separate emails.
  • Two roles exist:
  1. Admin – An admin can create buckets and users, set up read/write access control for users, and do everything a user can do; owns data created by users.
  2. Users – Users may access buckets and read or write data inside buckets if the admin granted access. Users cannot create buckets.


  • The system is not backed up.
  • Support will be provided during business hours on business days.
  • CISL will create only one admin account per lab. The admin will be able to create accounts for other users. Because the secret key-based logins do not expire, the admin will also delete accounts as appropriate – for example, when a user leaves NCAR.

Requesting account

Contact CISL to request an account. You will be asked to:

  • Specify how much disk space you need.
  • Give a brief description (one sentence) of your intended use case.
  • Acknowledge that you will be the admin and will manage buckets and users.

Documentation and additional information

This related page will help you get started as an object storage admin: Getting started with object storage admin account.

  • Additional documentation is attached below.
  • The system is accessible only via the NCAR VPN. This is important mostly for the browser-based access, since CISL anticipates that the server-based access will be from an internal server anyway.
  • The access and secret credentials will be sent via email. They are all it takes a user to login (there is no UCAS, CIT, or Duo login). The NCAR username is irrelevant for this system.
  • The way that these credentials are (unlike username/password) seems to nudge users towards nonoptimal patterns, such as hardcoding them into the source code. Users are strongly advised to NOT do that. Instead, use a separate file (outside of version control) similar to the following and source that file before running your code. This applies to both admin and user accounts.
export AWS_ACCESS_KEY_ID='xxx' 
  • Admins might want to create a separate user account for themselves with just reading (and perhaps writing) capabilities and not admin capabilities. This would require use of a different email address, since the system does not allow re-use of existing emails. Admins might use a personal email, or a (group) alias setup in PeopleDB.

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