Comment 1 for bug 1995758

> cache.disk.etag = "/var/cache/lighttpd/compress/cache_etag"

What is that? Where did it come from? Perhaps some third-party module?
That directive does not exist in the official lighttpd source upstream.

If things are not working for you, you should remove *all* optional settings and focus on getting things working before adding tuning settings. These are all optional and you should probably prefer the lighttpd defaults:
```
deflate.max-compress-size = 131072
deflate.min-compress-size = 0

deflate.params = (
  "BROTLI_PARAM_QUALITY" => 7,
  "BROTLI_PARAM_LGWIN" => 22,
  "BROTLI_PARAM_MODE" => 0,
  "ZSTD_c_compressionLevel" => 22,
  "gzip.level" => 9,
  "gzip.memLevel" => 9,
  "gzip.strategy" => 0,
)
```

Did you check that `deflate.cache-dir = "/var/cache/lighttpd/compress"` the directory exists and lighttpd has write permission?

Did you test by accessing a simple static file (with mimetype text/*) to see if the cache is filled? Have you checked that you are receiving a compressed response to your test HTTP request, even if the cache is not filled? If you're not receiving a compressed response to your test HTTP request, then mod_deflate is not handling the request for the static file.

Did you read through https://wiki.lighttpd.net/Docs_ModDeflate and check the Known Limitations section?

> - etag header is set and enabled by etag.use-size = "enable".

You should prefer to use lighttpd defaults unless you have read the lighttpd documentation for etags and really want to change it.

I also do not understand why this is not a forum post asking for assistance. This is unlikely to be a bug in lighttpd.