SaaS, PaaS and IaaS

Cloud means a lot of different things to different people. Sofwtare, Platform and Infrastructure as a service (SaaS, PaaS, and IaaS for those that like acronyms), are the three main types of cloud today.

How do you know which is best? Well think of it this way, the higher up the stack you go, the less work you need to do to get the benefits of it. Let me explain what I mean.

Salesforce.com is a SaaS company primarily. Their sales cloud is the offering that started the cloud shift. Salesforce.com customers, don't need to write code to leverage the application. In most cases you can use the user interface and pretty easily make new reports, or add new fields to existing forms etc. You get out of having to develop. You also don't need to patch, maintain, backup anything. They handle it all. The trade off is flexibility. You aren't in control of when you get upgraded to the next release, and can't make changes outside of the ones in the user interface.

Amazon web services, or Microsoft Azure are examples of PaaS. They handle all the machine related things, like patches, backups, making sure power is redundant etc. They also give you a great programming interface that lets you easily build new applications. The key here is YOU build the software, but not the operating system. It's a step up from having to make sure you have the latest version of SQL or Linux, but it's more work than using someones else's application. It also gives you more flexibility and control over upgrades of the software.

Infrastructure as a Service puts you back in charge of the operating system but still keeps you from having to worry about details like, redundant hard drives or plugging power supplies into different circuits. You maintain the operating system and have to worry about patches. You need to decide if you want SQL or Postgres for a database. You need to decide on a version of Apache or IIS etc. Then you have to build the application (or buy it of course).

All of these are designed to be scalable (both up and down) and can help avoid a big capital expense up front. The key is to decide how much flexibility you can trade for ease of use.