I have a networking issue I'm trying to solve.
I have two EC2 instances, same zone, same type.
On one of the two EC2 instances (the 'bad' instance), the download speed is really poor (200k/s), while on the other (the 'good' instance), the download speed is fine, comfortable at 30M/s +). To clarify, I'm talking about downloading files to the EC2 instance while ssh'd into the server, e.g running wget with a large file. I've tried different files, including S3 objects and a large linux ISO from elsewhere.
Running ethtool eth0 only returns 'Link detected: yes' for both.
When running ifconfig, both return the same for most part, aside from how the good instance shows no error packets yet the bad instance shows many, with the figure increasing by about 10 a second, even when I'm not actively running a download:
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:168372370 errors:5075643 dropped:0 overruns:0 frame:0
TX packets:122116480 errors:0 dropped:0 overruns:0 carrier:0
Both servers are configured the same, at least were supposed to be. How can I go about diagnosing the cause for the slow download speed? Is there anything particular to EC2 instances that could cause this?
Having trouble knowing where to start.
Thanks for any help!
Best Answer
If your instance is EBS-backed then stop the instance, wait a minute or two, and then restart it. That will cause the instance to be started up on different hardware and may resolve your issue.