TopolearnDefault settings are conservative; a few targeted changes give large gains, while cargo-cult tuning wastes time.
Start by measuring ($request_time, $upstream_response_time, a load-testing tool). Then the settings that usually matter:
Compression: gzip on; with gzip_types for text formats (HTML is always included) and gzip_min_length 1024. Level 4 to 6 is the sweet spot; higher costs CPU for little gain. Don't gzip images or video, which are already compressed. gzip_static on; serves precompressed .gz files from the build, costing no CPU. Brotli needs a third-party module.
Static files: sendfile on; sends file data inside the kernel; tcp_nopush on; sends headers and the file start together; tcp_nodelay on; (default) avoids delays for small keepalive writes. open_file_cache max=10000 inactive=30s; caches file descriptors and metadata for sites with many small files.
Connections: client keepalive_timeout (default 75s) and keepalive_requests (default 1000) control reuse; upstream keepalive avoids TCP and TLS setup to backends, often the biggest win for proxies. TLS session caching and HTTP/2 reduce handshakes.
Buffers: proxy_buffers and proxy_buffer_size sized for typical responses avoid writing to temp files; the error log warns "an upstream response is buffered to a temporary file" when they're too small. client_body_buffer_size does the same for uploads.
Example
http {
sendfile on;
tcp_nopush on;
keepalive_timeout 30s;
open_file_cache max=10000 inactive=30s;
open_file_cache_valid 60s;
gzip on;
gzip_comp_level 5;
gzip_min_length 1024;
gzip_types text/css application/javascript application/json image/svg+xml;
gzip_vary on; # Vary: Accept-Encoding for caches
proxy_buffer_size 16k; # response headers
proxy_buffers 16 16k; # body buffers per connection
server {
listen 80;
location /assets/ { root /var/www; gzip_static on; expires 1y; }
}
}Remember
- gzip text at level 4-6; gzip_static serves prebuilt .gz files
- sendfile, tcp_nopush and open_file_cache speed static serving
- Upstream keepalive and buffer sizing matter most for proxies
Watch out for
- Gzipping already-compressed images, burning CPU for no size gain.