CODEWITHSUNDEEP
amazon-web-servicesloadcpurds
Simos Fasouliotis
Simos Fasouliotis

Reputation: 1390

aws rds 100% cpu 2 vcores

i currently use T2.Micro RDS with SQL Express.

Due to a heavy load application running, there might be times that 1 request of a visitor might take 30 seconds to complete. This makes the RDS work 100% CPU. The result is any other visitor that goes to the website same time and during 100% CPU load, the website takes much longer to answer.

T2.micro has 1 vCPU. I'm thinking of upgrade to T2.medium with has 2 vCPU. The question is, if i have 2 vCPU will i avoid the bottleneck? Example, 1st visitor with 30 second request, uses vCPU #1 and second visitor comes same time, is he using vCPU #2 ? Will that help my situation ?

Also, i did not see any option in aws rds to see what CPU is that. Is there option to choose faster vCPU somehow ?

Thank you.

Upvotes: 0

Views: 1375

Answers (1)

Michael - sqlbot
Michael - sqlbot

Reputation: 178966

The operating system's scheduler automatically handles the distribution of running threads across all the available cores, to get as much work done as possible in the least amount of time.

So, yes, a multi-core machine should improve performance as long as more than one query is running. If a single, CPU-intensive, long-running query -- and nothing else -- is running on a 2-core machine, the maximum CPU utilization you'd probably see would be about 50%... but as long as there is more than one query running, each of them will be running on one of the cores at a time, and the system can actually move a thread anong the available cores as the workload shifts, to put them on the optimum core.

A t2.micro is a very small server, but t2 is a good value proposition. With all the t2-class machines, you aren't allowed to run 100% CPU continuously, regardless of the number of cores, unless you have a sufficient CPU credit balance available. This is why the t2 is so inexpensive. You need to keep an eye on this metric as well. CPU credits are earned automatically over time, and spent by using CPU. A second motivation for upscaling a t2 machine is that larger t2 instances earn these credits at a faster rate than smaller ones.

http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/t2-instances.html

Upvotes: 1

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