Amazon's S3 Gets An SLA

Amazon Web Services now has an SLA. S3 (storage) and EC2 (virtual servers) have been adopted by many web companies to save money, but until now they’ve just had to trust that the services would stay up (Radar post). Jeff Barr made the SLA announcement on the AWS blog:

I am very happy to announce that, effective October 1, 2007, The Amazon S3 Service Level Agreement is in effect.

This SLA has been in the works for a while and we take the commitments made in this document quite seriously. We knew that S3 had to meet the very high performance and reliability goals set by our internal clients. We strongly believed that meeting this level of operational excellence would be good enough for our external users as well. Before we published our SLA, we wanted to get a better sense of how our external developers were making use of S3. With well over 5 billion objects under management, we now understand the usage patterns and properties needed to make an informed commitment.

You can read the entire document to see how this will work. Basically, we commit to 99.9% uptime, measured on a monthly basis. If an S3 call fails (by returning a ServiceUnavailable or InternalError result) this counts against the uptime. If the resulting uptime is less than 99%, you can apply for a service credit of 25% of your total S3 charges for the month. If the uptime is 99% but less than 99.9%, you can apply for a service credit of 10% of your S3 charges.

The addition of an SLA for S3 is good news for companies that no longer wish to deal with their own physical infrastructure. EC2 is still in Beta, so it is not surprising that they have not added an SLA for that service (though hopefully it will come). However, S3 is still missing some features that Artur requested previously:

Change the T&C to at least promise to give paying customers a notice of a certain amount of days if they choose to shut the service down.

Publish their current uptime and availability to their customers.

Show you how many copies of a file exists, and how quickly a file uploaded to them becomes redundant.

Missing features or not this was a great move for Amazon and one that is surely to increase their sales.

Update: I missed the section in Amazon’s SLA where they talk about terminations. Amazon pointed this out and included the appropriate clause:

I saw your post this morning and noticed what I see as an inaccuracy.
You say at the bottom that AWS hasn’t changed it’s T&Cs to give
customers notice. That is incorrect–the updated agreement changed
this. Here’s a link to the agreement:, and the relevant text
pasted here:

“3.3.2. Paid Services (other than Amazon FPS). We may suspend your right
and license to use any or all Paid Services (and any associated Amazon
Properties) other than Amazon FPS, or terminate this Agreement in its
entirety (and, accordingly, cease providing all Services to you), for
any reason or for no reason, at our discretion at any time by providing
you sixty (60) days’ advance notice in accordance with the notice
provisions set forth in Section 15 below.

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