src/collectors/debugfs.plugin/README.md
debugfs.plugin gathers metrics from the /sys/kernel/debug folder on Linux
systems. Debugfs exists as an easy way for kernel developers to
make information available to user space.
This plugin is external, the netdata daemon spawns it as a long-running independent process.
In detail, it collects metrics from:
/sys/kernel/debug/extfrag (Memory fragmentation index for each order and zone)./sys/kernel/debug/zswap (Zswap performance statistics).No user action required.
The debugfs root directory is accessible only to the root user by default. Netdata
uses Linux Capabilities to give the plugin access
to debugfs. CAP_DAC_READ_SEARCH is added automatically during installation. This capability allows bypassing file read
permission checks and directory read and execute permission checks. If file capabilities are not usable, then the plugin is instead installed with the SUID bit set in permissions so that it runs as root.
| Metric | Scope | Dimensions | Units | Labels |
|---|---|---|---|---|
| mem.fragmentation_index_dma | numa node | order0, order1, order2, order3, order4, order5, order6, order7, order8, order9, order10 | index | numa_node |
| mem.fragmentation_index_dma32 | numa node | order0, order1, order2, order3, order4, order5, order6, order7, order8, order9, order10 | index | numa_node |
| mem.fragmentation_index_normal | numa node | order0, order1, order2, order3, order4, order5, order6, order7, order8, order9, order10 | index | numa_node |
| system.zswap_pool_compression_ratio | compression_ratio | ratio | ||
| system.zswap_pool_compressed_size | compressed_size | bytes | ||
| system.zswap_pool_raw_size | uncompressed_size | bytes | ||
| system.zswap_rejections | compress_poor, kmemcache_fail, alloc_fail, reclaim_fail | rejections/s | ||
| system.zswap_pool_limit_hit | limit | events/s | ||
| system.zswap_written_back_raw_bytes | written_back | bytes/s | ||
| system.zswap_same_filled_raw_size | same_filled | bytes | ||
| system.zswap_duplicate_entry | entries | entries/s |
To troubleshoot issues with the collector, run the debugfs.plugin in the terminal. The output
should give you clues as to why the collector isn't working.
Navigate to the plugins.d directory, usually at /usr/libexec/netdata/plugins.d/. If that's not the case on
your system, open netdata.conf and look for the plugins setting under [directories].
cd /usr/libexec/netdata/plugins.d/
Switch to the netdata user.
sudo -u netdata -s
Run the debugfs.plugin to debug the collector:
./debugfs.plugin