Aws ELB vs ALB review: performance, sustainability

Question

Almost a year has passed since aws deployed ALB.
It seems that there is practically no technical comparison between the classic LB and ALB.
The only thing my research has given is the aws forum question

While the foregoing implies that ALB is not reliable, it is only one source.
I am interested in learning about the experiences of people who have switched between ELB and ALB, mainly in terms of latency, resilience, HA.
It seems to me that Layer4 balancing is more reliable than Layer7, and therefore overall performance will be better.

Answer 1

I would like to provide my experience here, but I will not go into details. Basically, my company has more than 200 thousand devices on the field, actively connecting our server through websocket. We used ELB on our servers, and it worked quite well, all connections were pretty stable. Previously, we tried to switch ELB to ALB, but the result was not very good, and we switched back.

The main problem that we discovered was unexpectedly turned off (with a picture, how every 15 hours?). Please check the graph of the number of connections that I captured from the monitoring system:

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