My definition of IT system cloud index

09 July 2013

The objective of the "cloud index" is to monitor the cloud level of an IT system in order to monitor and to communicate in a simple way to the level of cloud reached.

Here's the definition I use.

The IT system is defined as a sum of Business Services (i.e. applications, see ITIL definition).

Each business service is characterized by a "feature_size".

The "feature_size" express the complexity of the application (kind of  "function point" approach).

For each business service, we express it's "cloud_level" on a scale from 0 to 100 :

  * **0****  ** : the business service is hosted on dedicated servers on premise
  * **10** : the business service is hosted on shared servers (via virtualization for example) on servers on premise.
  * **20** : the business service is hosted on an external datacenter
  * **50** : the business service is hosted on a IaaS platform
  * **60** : the business service is on a PaaS platform
  * **100** : the business service is supported by a full Saas Solution.

Based on this, the cloud index is defined as the weighted average of the business services "cloud_level" weighted by the "feature_size".