Tweaks for API Nodes

[abitmore]

Learnt one more trick to improve performanceresponse time for API nodes (do it before starting a node):

sudo sysctl -w net.core.somaxconn=65535
ulimit -n 65536

Need to document this somewhere.

Benchmark data is welcomed.

//Update:
According to https://www.nginx.com/blog/tuning-nginx/:

• net.core.somaxconn – The maximum number of connections that can be queued for acceptance by NGINX. The default is often very low and that’s usually acceptable because NGINX accepts connections very quickly, but it can be worth increasing it if your website experiences heavy traffic. If error messages in the kernel log indicate that the value is too small, increase it until the errors stop.

Note: If you set this to a value greater than 512, change the backlog parameter to the NGINX listen directive to match.

And there are more info about rate-limiting on the page. Also quoted here: #843 (comment)

More info: https://steemit.com/witness-category/@someguy123/guide-optimise-your-rpc-server-for-better-performance

[abitmore]

OP updated.

[pmconrad]

That setting doesn't increase performance, it only expands the connection queue so that fewer connections will be rejected. This is mostly useful if you have many short-lived connections, probably less so for our websocket-based API.

[abitmore]

More info: https://steemit.com/witness-category/@someguy123/guide-optimise-your-rpc-server-for-better-performance

[abitmore]

Use ulimit -n 65536 to enable more connections.