We want to use provisioned IOPS EBS volume on our mongo machines, I'm a bit confused on how to calculate the number of provisioned IOPS to use.
Currently we're getting an average of 25 IOPS (read + write) per volume (we use 4 EBS volumes combined), we're also seeing that our CPU is in 'waiting' state during the peak IO times.
I can split the question into two parts -
- Will we see a major increase in the average IOPS after moving to the provisioned EBS IOPS, because the IO latency will decrease, should we take a big buffer to avoid exceeding the IOPS count?
- How would you calculate the optimal number of provisioned IOPS for your mongo setup?
Edit - Attached the volume average queue length from amazon
(I can't paste the image so here's a link)