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EC2 Burstable Instances

Links: 114 AWS SOA Index

EC2 Burstable Instances

  • T2/T3 family.
  • When the machine needs to process something unexpected (a spike in load for example), it can burst, and CPU can be VERY good.
    • Burst credits are accumulated over time while your instance is running.
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    • If the machine bursts, it utilises burst credits.
    • If the burst credits are utilised the CPU becomes very bad, the CPU utilisation drops.
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  • Burstable instances can be amazing to handle unexpected traffic and getting the insurance that it will be handled correctly.
  • If your instance consistently runs low on credit, you need to move to a different kind of non-burstable instance.
    • Choosing and instance with higher vCPU.
  • Different instances earn credits at different rates.

T2/T3 Unlimited

  • It is possible to have an unlimited burst credit balance.
  • You pay extra money if you go over your credit balance, but you don't lose in performance.
  • Be careful, costs could go high if you're not monitoring the CPU health of your instances.
We CANNOT buy CPU credits.

So if we are running out of credits then our options are: - Turn on t* Unlimited. - Upgrade to non-t* type of EC2 instance. - Upgrade the EC2 instance type to t2.medium or higher.

Last updated: 2023-03-02