I'm executing a Spark job on EMR. The job is currently being bottlenecked by network (reading data from S3). Looking at metrics in Ganglia, I get a straight line at around 600 MBPs. I'm using i2.8x large instance type which is suppose to give 10Gbps i.e. ~ 1280MBPs. I have verified that enhanced networking is turned on and VirtualizationType is hvm, Am I missing something? Is there any other way to increase network throughput?
Networking capacity of Amazon EC2 instances is based upon Instance Type. The larger the instance, the more networking capacity is available. You are using the largest instance type within the i2 family, so that is good.
Enhanced Networking lowers network latency and jitter and is available on a limited number of instance types. You are using it, so that is good.
The i2.8xl is listed as having 10Gbps of network throughput, but this is limited to traffic within the same Placement Group. My testing shows that EMR instances are not launched within a Placement Group, so they might not receive the full network throughput possible.
You could experiment by using more smaller instances rather than fewer large instances. For example, 2 x i2.4xlarge cost the same as 1 x i2.8xlarge.