Why do we need queue length for for EBS

[ishan-sharma]

A company has a High Performance Computing (HPC) cluster that is composed of EC2 Instances with Provisioned IOPS volume to process transaction-intensive, low-latency workloads. The Solutions Architect must maintain high IOPS while keeping the latency down by setting the optimal queue length for the volume. The size of each volume is 10 GiB.

Which of the following is the MOST suitable configuration that the Architect should set up?

Right answer – Set the IOPS to 500 then maintain a low queue length.

The answer explanation is quite complex to understand, Why do we need queue length for for EBS? How do we calculate it

Can somebody pls explain the same in simpler words.

[TutorialsDojo-Support]

Hi Ishan,

Thank you for your feedback.

The queue length is the number of read or write operations waiting to be completed on an EBS volume. When you use Amazon EBS Provisioned IOPS volumes, you will want to deliver optimal levels of input/output performance based on your workload.

You need to match the EBS volume workload to the IOPS you provisioned. If the IOPS demand is higher than what you provisioned and the application is latency sensitive, consider using a Provisioned IOPS (SSD) volume with more provisioned IOPS. If I/O latency is high, you can check the average queue length to be sure that your application is not trying to drive more IOPS than you provisioned.

On this question, the company is using an HPC cluster that has transaction-intensive, low-latency workloads. So adjusting the volume’s provisioned IOPS based on the workload makes sense.

For computation, any volume 640 GiB in size or greater allows provisioning up to a maximum of 32,000 IOPS. Therefore, (32000/640) = 50 IOPS/GB. So for the 10GB volume, and you want to maximize IOPS, you can set it to 500 IOPS (50 IOPS x 10GB).

https://aws.amazon.com/premiumsupport/knowledge-center/optimize-ebs-provisioned-iops/

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-io-characteristics.html

Hope this helps.

Regards,

Kenneth Samonte @ Tutorials Dojo

[ishan-sharma]

so basically its 50 times the GB of volume given in the question

[youssef-baiji]

I dont understand this question either , why you calculating based on 640 GB and 32000 IOPS , I thought the maximum for IOPS for IO is 64,000 per volume