Skip to content

Significant changes to Puhti & Mahti authentication came in April! Read about the SSH key and multi-factor authentication requirements.

Terms and concepts

Access Control List

The Access Control List (ACL) mechanism can be used to control other Allas users' access to your buckets.

Billing unit

Billing units describe the consumption of computing and storage resources in the CSC systems. In Allas, the amount of data stored consumes billing units.

See Billing and Quotas

Bucket

A bucket is a container for objects that may also include metadata describing the bucket.

Checksum

A checksum is a hashed string computed of an object to observe whether the object has changed (data integrity). You can display the checksum using the command md5sum.

Client

The client software is used to access an object storage service, such as Allas. Allas can be accessed with several different clients.

Metadata

Metadata describes an object or bucket. It can be used to search for objects. It is used via key-value pairs (for example, name: John).

Object lifecycle

Object lifecycle Can be configured to automatically remove objects from Allas. Lifecycle is configured in the bucket level, where multiple expiration periods can be defined. Lifecycle is applied to the objects in the bucket based on their matching tags and/or prefixes. See an example in the s3 client tool documentation

Object storage

Object storage refers to a computer data storage that manages data as objects instead of files or blocks. Typically, an object consists of the data itself, metadata and a unique identifier. In general, the data can be anything, e.g. an image or audio.

OpenStack

The OpenStack cloud management middleware_ can be used to access Allas.

Pseudo folder

Buckets cannot contain other buckets. You can, however, use so-called pseudo folders.

If an object's name contains a forward slash /, it is interpreted as a folder separator. These are shown as folder listings when accessing the data via come clients, for example the web interfaces. These pseudo folders are automatically added if you upload whole folders using a command line client.

For example, if you add two objects 

fishes/salmon.png
fishes/bass.png
in a bucket, listing the bucket will display a folder called fishes and the two files in it.

Quota

The Allas quota defines the maximum amount of data (capacity) the project is allowed to store in Allas.

See Billing and quotas