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A central cloud service is the ability to store and retrieve objects. An object can for instance be a regular file. The NTNU OpenStack installations (SkyHiGh, stack.it) provides API's for storing and retrieving objects. Objects can be stored with access control, or publicly, depending on the users requirements.
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To find the API url you should use the command "openstack catalog show swift", and select the public URL from that command. When using S3 you should remove the "/swift/v1/<project-id" from the url.
Storage resilliency
The object storage solutions should be a safe space to store data. A very important aspect of this is to ensure that information stored here should not be lost. There are two levels of resilliency available, which are further described in this section.
Regardless of which level of resilliency you choose, all objects stored in this storage service will be replicated to three physical storage-servers. Should one of our storage-servers malfunction, there wil be at least two copies of all the data left, and a third copy would be created as soon as possible. The same will happen if a harddrive malfunctions. The storage-cluster is thus self-healing, and would hence provide a much safer storage than a regular harddrive or a regular file-share.
The object storage solution is not backed-up to any offline storage media (tapes). This means that there will be three copies of your data, but if you delete an object yourself, the object will be deleted. We will ensure to have multiple copies of all non-deleted data
Default containers
The default containers/buckets support mainly the following operations:
- Upload (PUT): Objects can be uploaded to a certain container, and given a certain name. If there is an object with the given name in the current container, that object will be overwritten (DELETE, then PUT).
- Download (GET): Existing objects can be downloaded. If the container is private (that is the default) a user needs to be authenticated first to be allowed to download the object.
- Delete (DELETE): Objects can be deleted. This will make all the three copies of this object being removed from the permanent storage, and the object will quickly become unavailable.