Technologies/NGINX/nginx_upstream_peers_fails
NGINXNGINXMetric

nginx_upstream_peers_fails

The total number of unsuccessful attempts to communicate with the server.
Dimensions:None
Available on:DatadogDatadog (1)
Interface Metrics (1)
DatadogDatadog
The total number of unsuccessful attempts to communicate with the server.
Dimensions:None
Sources
nginx.upstream.peers.failsgithub.com
Related Insights (2)
Upstream Connection Pool Saturation Blocks NGINX Workerscritical

When NGINX proxies to backends (PHP-FPM, FastCGI, uwsgi) without proper connection limits, a single site can exhaust the proxy connection pool, blocking other sites on shared infrastructure. Default mod_proxy behavior allows each child process to open max connections equal to ThreadsPerChild × ServerLimit.

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HTTP Error Rate Spikes Require Multi-Layer Analysiscritical

Increases in nginx_server_zone_responses_4xx or nginx_server_zone_responses_5xx require differentiation between client errors (4xx), NGINX configuration issues (502/503), and upstream failures (504, backend 5xx). The same metric can indicate completely different root causes depending on code distribution.

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