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Case Study: Analyzing Amazon Cloud Services SLA

“The customer is always right. Until you read the fine print” (popular saying). 

Previously, Google Apps SLA was reviewed. Now it’s time to perform an Amazon review on SLA (you can read it here).

The first thing to take into account when one analyzes an SLA is the compensations model. An agreement is only as strong as the compensations and how they are triggered (whereby who is responsible for identifying and communicating any deviation). One can agree to a very high availability (i.e. 99.9%). But if nothing happens (i.e. penalties are too low) when promises aren’t delivered, the agreement is as worthy as wet sheets.

Let’s just start at the end. What happens if Amazon doesn’t deliver to you the agreed upon service level? In that case Amazon gives you Service Credits.

Ok, so what are Service Credits? They are a discount percentage on future bills: 25% if availability is less than 99%, and 10% if availability is equal to or greater than 99% but less than 99.9%. Amazon says “Service Credits will not entitle you to any refund or other payment from AWS.”

The compensation model also states “Service Credits may not be transferred or applied to any other account.” And “Unless otherwise provided in the AWS Agreement, your sole and exclusive remedy for any unavailability, non-performance, or other failure by us to provide Amazon S3 is the receipt of a Service Credit (if eligible) in accordance with the terms of this SLA.”

But, that’s not all, you need to request your Service Credits and Amazon will determine if you are eligible. Amazon says:

“To be eligible, the credit request must be received by us by the end of the second billing cycle after which the incident occurred and must include:

i. the words “SLA Credit Request” in the subject line;
ii. the dates and times of each incident of non-zero Error Rates that you are claiming; and
iii. your request logs that document the errors and corroborate your claimed outage (any confidential or sensitive information in these logs should be removed or replaced with asterisks).

If the Monthly Uptime Percentage applicable to the month of such request is confirmed by us and is less than 99.9%, then we will issue the Service Credit to you within one billing cycle following the month in which your request is confirmed by us. Your failure to provide the request and other information as required above will disqualify you from receiving a Service Credit.”

Finally, Amazon adds in its Exclusions point: “If availability is impacted by factors other than those used in our calculation of the Error Rate, then we may issue a Service Credit considering such factors at our discretion.

So the conclusions are the following:

  • You need to ask for your compensation by submitting a claim request (Amazon is not proactive).
  • If you choose cloud services for not investing in infrastructures, you are wrong. Because you are required to invest in external monitoring services if you want to have any SLA. Here, the problem is that, for being able to submit your claim request, you are required to demonstrate this fact with your own logs documenting the outage.
  • Availability objectives defined by Amazon have no business orientation. They are calculated in 24×7, when you probably don’t have users. For example, an 99% availability in 24×7 means that from the total of 43,200 monthly minutes, you can be 432 minutes without service (i.e. 7.2 hours). Now, if in fact your users work only 8×5, that 7.2 hours could be nearly a whole working day. The Amazon penalty in this case would only be a 10% of a future bill. 
  • Availability is calculated how Amazon decides “at their discretion”.
  • It’s very ironic, because if you want to have any compensation from a major loss caused by an Amazon’s outage, you are obligated to continue contracting their services as you only receive a small discount on future bills. Finally, to top it all off, Service Credits may not be transferred and you are stuck with them.

With this SLA you can be completely confident and secure in knowing that you will never receive any compensation at all.

Now, having reviewed Google Apps and Amazon cloud services, we could distinguish between “Traditional SLA-guaranteed” services and “Cloud best-effort” services.

It’s up to you what to choose! But, please tread carefully. Think beforehand what an outage would cost your business.

What is your opinion about Amazon Cloud Services SLA?

Author: Angel Berniz (All Rights Reserved by the authors).

Source: Original Text (based upon first hand knowledge).
Image:  © chariclo –
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