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Ok so I am going through A Cloud Guru's course for the solutions architect associate and I am having trouble understanding what IOP burst are. Here are the notes from the course: 

EBS Volume Types
   General Purpose SSD (GP2)
     General purpose, balances both price and performance.
     Ratio of 3 IOPS per GB with up to 10,000 IOPS and the ability to burst up 
     to 3000 IOPS for extended periods of time for volumes under 1Gib.

After doing some research I understand IOPS to mean input/output operations. Meaning read and write to disk I assume. What I don't understand about this is, what does it mean to have 3IOPS per Gig. Does that mean for every gig of space on the drive you can read/write 3 times to the disk? That doesn't seem right. The other part I don't understand is what does "the ability to burst" mean? My guess is that means how much can be read/written at once over the course of the read/write operation but I'm just guessing.

Kara
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user3756741
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    AWS re:Invent 2016 talk on EBS explaining burst - https://www.youtube.com/watch?v=1AHmTmCkdp8 – Curious Nov 15 '17 at 12:59

1 Answers1

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Actually, IOPS means Input/Output PER SECOND. When you choose your EBS Type it has a baseline IOPS value, meaning that the quantity of operations per second is limited by the volume architecture.

With 3000 IOPS/Gib you have 3000 operations of input/output per second, with the capacity to transfer 1Gib. There are some techinal details here that I'm no the best one to tell you about block sizes and all. But this is a summary.

One thing you must understand is that the IOPS is not just a techical thing but also a comercial thing for Amazon. They sell the EBS with a limited IOPS (baseline), but if you need more IOPS you can pay an extra and create volumes with Provisioned IOPS (that can fo up to 20000).

About the burst, what I tell here is not exactly how it works, but can help you understand a little more that you undersand now. Some volumes can upgrade your IOPS for a brief periodo of time in case is needed without extra costs. This is a temporary burst, an normally with works for just a few minutes. It means that if receive a request for data that extends your defined IOPS, the service will provide with more of your defined for a brief period, to keep your service quality consistent. But if you need it for a long period will need to pay for it.

I think that this burst is based on some type of credits, like if you don't use your availabe IOPS for a time it generate some credits to be used in burst. But this last information must be confirmed with more experienced people.

Gustavo Tavares
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  • Thanks for explaining. Since I'm taking the associate exam I only need a general u understanding of what these concepts mean. – user3756741 Jul 05 '17 at 17:37