🔗 What Debug Sections and debug_options in squid.conf are all about
Sometimes people need to see more than just the fatal or critical problems occurring within Squid.
Squid contains its own debugging system broken into sections and levels.
- Section means a component within squid that does some particular operation.
- Level means the amount of information needed about any given section.
They are configured in squid.conf with the debug_options setting as a list of Section,Level pairs. Each pair is set left-to-right. If a section is mentioned twice the last mentioned level is used.
Generally only ALL,0 is used, to display any major issues in need of urgent fix. These are problems fatal to squid and if your squid is crashing the problem is mentioned in cache.log at level 0.
Administrators may also set debug_options ALL,1 to get a report of issues which are not causing critical problems to squid, but which may be fatal to certain client requests. These messages usually also indicate network issues the admin should be looking at fixing.
Higher debugging levels are available if an issue needs tracking step-by-step through the code. They go up to 9, though 6 contain most information needed by the developers to debug.
🔗 What the Levels mean
- Critical issues only. No debug information at all.
- Always displayed
- These are problems fatal to squid and if your squid is crashing
the problem is mentioned in cache.log at level 0.
currently Startup, Shutdown and Reconfigure do produce output at this level.
- Important issues.
- Default Squid behaviour is to log at this level unless otherwise configured
- These messages usually indicate network issues the admin should be looking at fixing.
- Protocol Traffic. Generally used only by the high-level protocol sections (eg. sections 9-12).
- Legacy debugs
- Section specific info a developer once thought to be important enough to highlight for troubleshooting.
- Most useful debug information is displayed at this level.
- More detail of debug information, if level-5 is not displaying enough about a specific problem.
- Some section specific debug information not commonly useful. (eg lock counting).
- Raw I/O data. May contain privacy or security sensitive information. Guaranteed to generate very large cache.log.
🔗 What the Section numbers mean
We take great pains to keep debug sections consistent across releases. The current catalog of debug sections is at https://github.com/squid-cache/squid/blob/master/doc/debug-sections.txt
Categories: KnowledgeBaseNavigation: Site Search, Site Pages, Categories, 🔼 go up