SSD over provisioning on AWS EC2


I thought I read somewhere that on aws ec2 there is no need to over provision the disks, however, I was just reading this and it seems like i2 instances do not come over-provisioned. What’s the final word on this?

SSD controllers can use several strategies to reduce the impact of write amplification. One such strategy is to reserve space in the SSD instance storage so that the controller can more efficiently manage the space available for write operations. This is called over-provisioning. The SSD-based instance store volumes provided to an I2 instance don’t have any space reserved for over-provisioning. To reduce write amplification, you should leave 10% of the volume unpartitioned so that the SSD controller can use it for over-provisioning. This decreases the storage that you can use, but increases performance.


Hi, I’ll look into this and share what I find with you

I spoke to our tuning and SSD specialists and the view is that Aerospike guidance should take precedence as this has been established based on our own testing with our ACT tool. While this may change if Amazon change their infrastructure, right now we recommend that you stick with the Aerospike suggestions which can be found here:

You were right when you said you had read that we do not recommend manually over provisioning SSDs on Amazon i2 instances.


Great - thanks for confirming!