BCache

Plugin: proc.plugin Module: /sys/fs/bcache

Overview

Statistics for BCache (block layer cache) devices, including cache hit ratios, I/O operations, cache allocations, and bypass activity.

This collector is only supported on the following platforms:

• Linux

This collector supports collecting metrics from multiple instances of this integration, including remote instances.

Default Behavior

Auto-Detection

Automatically detects BCache devices by reading stats from /sys/block/*/bcache/.

Limits

The default configuration for this integration does not impose any limits on data collection.

Performance Impact

The default configuration for this integration is not expected to impose a significant performance impact on the system.

Setup

Prerequisites

No action required.

Configuration

Options

There are no configuration options.

via File

The configuration file name for this integration is netdata.conf.

The file format is a modified INI syntax. The general structure is:

[section1]
    option1 = some value
    option2 = some other value

[section2]
    option3 = some third value

You can edit the configuration file using the edit-config script from the Netdata config directory.

cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata
sudo ./edit-config netdata.conf

Examples

There are no configuration examples.

Alerts

The following alerts are available:

Alert name	On metric	Description
Alert name bcache_cache_dirty	On metricdisk.bcache_cache_alloc	Descriptionpercentage of cache space used for dirty data and metadata (this usually means your SSD cache is too small)
Alert name bcache_cache_errors	On metricdisk.bcache_cache_read_races	Descriptionnumber of times data was read from the cache, the bucket was reused and invalidated in the last 10 minutes (when this occurs the data is reread from the backing device)

Metrics

Metrics grouped by scope.

The scope defines the instance that the metric belongs to. An instance is uniquely identified by a set of labels.

Per disk

Labels:

Label	Description
device	TBD
mount_point	TBD
device_type	TBD

Metrics:

Metric	Description	Dimensions	Unit
disk.bcache_cache_alloc	BCache Cache Allocations	ununsed, dirty, clean, metadata, undefined	percentage
disk.bcache_hit_ratio	BCache Cache Hit Ratio	5min, 1hour, 1day, ever	percentage
disk.bcache_rates	BCache Rates	congested, writeback	KiB/s
disk.bcache_size	BCache Cache Sizes	dirty	MiB
disk.bcache_usage	BCache Cache Usage	avail	percentage
disk.bcache_cache_read_races	BCache Cache Read Races	races, errors	operations/s
disk.bcache	BCache Cache I/O Operations	hits, misses, collisions, readaheads	operations/s
disk.bcache_bypass	BCache Cache Bypass I/O Operations	hits, misses	operations/s