Making Quick EC2 Cost Savings

Allowing teams easy access to Amazon Web Services can do wonders for productivity. It can also cost a small fortune. Maybe you’ve been shocked by a hefty bill recently, but what can you do about it? Here’s a quick list of simple ways to bring that bill down next.

Get rid of instances that are not being used

Cost saving per instance: 100%

Obvious really, isn’t it? You may have even mentioned it in meetings, now and again, to mutterings of “yes, yes, we’ve done that”.   Have they indeed?

Feel happy and satisfied when you can see a spreadsheet, or scrap of paper passed around with instances being ticked off. Buy them pizza. It’s a boring task.

Resize instances that are over-sized

Cost saving per instance: typically around 30%

Developers often tend to overestimate the resources they need. Sometimes it’s better to over-estimate than underestimate, but perhaps Amazon CloudWatch can help bring a little reality to the situation.

Turn instances of when they’re not being used

Cost saving per instance: approximately 65%

Let’s suppose we could turn off development and test instances after 7pm and back on again at 7am, and off all weekend.

Amazon to not charge for instances that are turned off (see http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Stop_Start.html). This only applies to instances with EBS storage, but note that the EBS storage is still charged for when the instance is off.

Now is the time to find out how slick your development systems are. Suppose the engineers need to work late, or at weekends. Can they bring the instances back up when they need them?

Here’s the costing to back up the 65% claimed saving:

Using Amazon’s pricing calculator (http://calculator.s3.amazonaws.com/index.html)

1 x t2.medium instance, with 20GB EBS volume attached (no free usage).
100% instance utilisation: $39.07

36% (5/2/7) instance utilisation during the week, and no use at weekends: 39.07*2.5/7 = $13.73

Saving: 1-(13.73/39.07) = 65%

Buy instances with 1 year partial up front payment, rather than on demand

Cost saving per insfance: typically 30%

Can you plan a year ahead?  You may not know what you need next year, but you might know that you’ll still be using Amazon.  Reserved instances can be moved around, so there is quite a bit of flexibility. However, it is a commitment to purchase an entire year’s computing, pegged at a given price

In Summary

These are quite simple steps that can be taken to reduce Amazon costs, with substantial savings. However, every change requires effort, and sometimes it can be difficult to get the time to make the savings.

If you need a hand, why not get in touch and see if we can help. It’s one of our specialities!

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