Service Level Agreements (SLAs) appear to finally be maturing in the realm of Web performance. Both of the Web performance companies that I have worked for have understood their importance, but convincing the market of the importance of these metrics has been a challenge up until recently.

In the bandwidth and networking industries, SLAs have been a key component of contracts for many years. However, as Doug Kaye outlined in his book Strategies for Web Hosting and Managed Services, SLAs can also be useless.

The key to determining a useful Web performance SLA rests on some clear business concepts: relevance and enforceability. Many papers have been written on how to calculate SLAs, but that leaves companies still staggering with the understanding that they need SLAs, but don’t understand them.


Relevance is a key SLA metric because an SLA defined by someone else may have no meaning to the types of metrics your business measures itself on. Whether the SLA is based on performance, availability or a weighted virtual metric designed specifically by the parties bound by the agreement, it has to mean something, and be meaningful.

The classic SLA is average performance of X seconds and availability of Y% over period Z. This is not particularly useful to businesses, as they have defines business metrics that they already use.

Take for example a stock trading company. in most cases, they are curious, but not concerned with their Web performance and availability between 17:00 and 08:00 Eastern Time. But when the markets are open, these metrics are critical to the business.

Now, try and take your stock-trading metric and overlay it at Amazon or eBay. Doesn’t fit. So, in a classic consultative fashion, SLAs have to be developed by asking what is useful to the client.

  • Who is to be involved in the SLA process?
  • How do SLAs for Internal Groups differ from those for External vendors?
  • Will this be pure technical measurement? Will business data be factored in?

Asking and answering these questions makes the SLA definition process relevant to the Web performance objectives set by the organization.


The idea that an SLA with no teeth could exist is almost funny. But if you examine the majority of SLAs that are contracted between businesses in the Web performance space today, you will find that they are so vaguely defined and meaningless to the business objectives that actually enforcing the penalty clauses is next to impossible.

As real world experience shows, it is extremely difficult for most companies enforce SLAs. If the relevance objectives discussed above are hammered out so that the targets are clear and precise, then enforcement becomes a snap. The relevance objective often fails, because the SLA is imposed by one party on another; or an SLA is included in a contract as a feature, but when something goes wrong, escape path is clear for the “violating” party.

If an organization would like to try and develop a process to define enforceable SLAs, start with the internal business units. These are easier to develop, as everyone has a shared business objective, and all disputes can be arbitrated by internal executives or team leaders.

Once the internal teams understand and are able to live with the metrics used to measure the SLAs, then this can be extended to vendors. The important part of this extension is that third-party SLA measurement organizations will need to become involved in this process.

Some would say that I am tooting my own horn by advocating the use of these third-party measurement organizations, as I have worked for two of the leaders in this area. The need for a neutral third-party is crucial in this scenario; it would be like watching a soccer match (football for the enlightened among you) without the mediating influence of the referee.

If your organization is now considering implementing SLAs, then it is crucial that these agreements are relevant and enforceable. That way, both parties understand and will strive to meet easily measured and agreed upon goals, and understand that there are penalties for not delivering performance excellence.