I have a t1.micro instance with 8GB of magnetic EBS volume as it's root disk with a LAMP environment on it. I thought that I will upgrade it to t2.micro with 8GB of General Purpose SSD volume.

However I read that the magnetic storage has ~100 IOPS, and the SSD has 3 * size, so it would be only 24 IOPS. Do I understand it well that any SSD volume that is smaller than 33GB would perform slower than the old magnetic storage?


Quote from Amazon: "General Purpose (SSD) volume types have a baseline IOPS of volume size X 3 and can burst up to 3000 IOPS for 30 minutes."

What does baseline mean? How is that 30 minute calculated? Would my 8GB SSD be able to burst up to 3000 IOPS for 30 minutes every hour/day/month?

  • Also would love to hear what exactly "bursting for 30 minutes" means. Feb 19 '15 at 9:15

You forgot the burst capacity. For both EBS magnetic and General purpose SSD, the "base" speed is as you said. Base speed is the minimuum guaranteed speed in any moment. But, while with magnetic disks you have a burst capacity of a "few hundreds", with SSD you can go up to 3000 iops. It then depends on what use you make of your machine: need stable constant i/o performance on a small disk through the whole day? Go magnetic. Have the casual I/O spike (reboots, a few minutes of heavy traffic, your night backup process)? Perfect scenary for the general purpose SSD.

  • So what you are sayning is that if prices should be the same, then SSD has more storage but slower IOPS, and magnetic has faster IOPS but has less storage? Aug 15 '15 at 1:09
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    @Assassinbeast please read the EC2 docs here regarding volume types. Amazon guarantees a minimum performance on SSD volumes that depends on the size of the volume that you buy. With their magnetic volumes instead, they provide a steady minimum performance. For very small volumes with a balanced workload then, the magnetic choice might be better than a small SSD volume.
    – stoned
    Aug 16 '15 at 19:55

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