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Technical Description

Some more technical details to Contabo's S3 compatible Object Storage.


We are using Ceph for providing S3 compatible Object Storage.

  • Virtual Hosted Buckets are not supported. Path based buckets are being used. so e.g. is used instead of
  • Custom domain names are supported. Please check Setup Custom Domain
  • No server side encryption yet
  • Transport is encrypted via TLS


Limitation is performed to assure good and fair performance for all users of the Object Storage system. Limitiations can be adjusted anytime depending on current usage.

  • max. file size is 5 TB
  • number of objects is by default limited to 3 millions per customer
  • number of S3 API requests are by default limited to 250 requests / second
  • every data stored has additional 3 times redundancy
  • no additional backup is performed
  • bandwidth is limited and regularily adjusted. The default limit is 10 MByte/s (=80 Mbit/s). Please be aware that the actual bandwith depends on various circumstances, e.g. personal internet connection speed and current load situation on Object Storage system.
  • by default max. 100 buckets per customer
  • if publicly shared objects are set to private, they can still be publicly available for up to one hour due to caching

ARN (Amazon Resource Name) Format

The ARN are used to specify resources like users.

In case you are e.g. building up your own polcies you might have the need to specify users like e.g. Restricting Users to Buckets

ARN Format for Customer (Main User)


  • To get your s3TenantId please use cntb get objectStorages -o=json

Example: arn:aws:iam::5c37e60c3ee04f1eb116c436b1afadca:user/12345

ARN Format for Users of Cutomer (Sub Users)


  • To get your s3TenantId please use cntb get objectStorages -o=json
  • The userId is obtained by using cntb get users

Example: arn:aws:iam::5c37e60c3ee04f1eb116c436b1afadca:user/12345:3368c22e-08da-446f-a470-1928e58457a2