The following is a list of disadvantages and advantages of SaaS, PaaS and IaaS in comparison to one another.
- The most cost effective Cloud service as you only lease the software and not the resource.
- SaaS requires minimal planning and is easy to setup, as applications are usually simple in usage and readymade.
- Rapid deployment as the software is fully provisioned on demand.
- The customer does not need to worry about the management of applications, as this is all handled by the provider.
- Software is usually very stable, as it is supported by the Cloud provider’s large infrastructure and I.T team.
- The customer has no control over the system processing its data.
- There is no control over which customers use the software; the software is used by a large amount of users. An example of SaaS would be Dropbox.
- Little or no control over the parameters of software.
- Little control over deployment, upgrade and testing methodology (e.g. Dev, UAT, Live systems availability)
- Currently only a limited number of software solutions are offered in the form of SaaS.
- Integration with other software on any other systems is either difficult or unsupported (e.g. single sign-on)
- Cloud provider has full access to customers’ data, unless cryptography is used (But this would mean no processing could be done on the Cloud thus reducing the usefulness of the Cloud).
- Still cost effective in comparison to IaaS, as you are still essentially leasing the software platform not a resource. An example of PaaS would be IIS.
- Unlike SaaS you can bring your own software to run on the platform therefore you have full control of software.
- Full control over the users accessing the software and the processing of data (to a certain extent, due to little knowledge of underlying VM and insider threat).
- Improved support for integration with other systems due to the above.
- Minimal management of the VM, as this is still handled by the provider.
- No Control over the VM or processing of data, this is a big security risk as you don’t know what’s happening with your data.
- Possibly no control over platform depending on Cloud provider.
- Platform is most likely a shared platform, for example there could be other customers running different websites on the same IIS platform.
- Management task can become time consuming and tedious as you are responsible for updates and upgrades of application.
- Not as cost effective as SaaS and not as much control over VM as IaaS.
- Customers have full control over their VM and everything inside it; customers can choose to automate the provisioning or build their own VM.
- A customer can run anything they want inside their VM.
- Full control of processing inside VM.
- Simplifies Integration with enterprise infrastructure
- Potential the most secure Cloud service using a PuC due to greater control of VM.
- The customer in essence can run and control its own virtual infrastructure without the overheads of cost and maintenance from running its own hardware.
- Most expensive, since the customer is now leasing a tangible resource, the provider can charge for every Cycle, bit of RAM or disk space used.
- Customer responsible for backups
- Unlike with SaaS or PaaS, customer is responsible for all aspects of VM Management.
- Still no control over which server or the physical (geographical) location of the VM.
Following is an illustration that depicts the differences between the cloud services types: