telegraf/plugins/inputs/system/DISK_README.md

Disk Input Plugin

The disk input plugin gathers metrics about disk usage.

Note that used_percent is calculated by doing used / (used + free), not used / total, which is how the unix df command does it. See https://en.wikipedia.org/wiki/Df_(Unix) for more details.

Configuration:

# Read metrics about disk usage by mount point
[[inputs.disk]]
  # By default, telegraf gather stats for all mountpoints.
  # Setting mountpoints will restrict the stats to the specified mountpoints.
  # mount_points = ["/"]

Additionally, the behavior of resolving the mount_points can be configured by using the HOST_MOUNT_PREFIX environment variable. When present, this variable is prepended to the mountpoints discovered by the plugin before retrieving stats. The prefix is stripped from the reported path in the measurement. This settings is useful when running telegraf inside a docker container to report host machine metrics. In this case, the host's root volume should be mounted into the container and the HOST_MOUNT_PREFIX and HOST_ETC environment variables set.

docker run -v /:/hostfs:ro -e HOST_MOUNT_PREFIX=/hostfs -e HOST_ETC=/hostfs/etc telegraf-docker

Measurements & Fields:

• disk
  • free (integer, bytes)
  • total (integer, bytes)
  • used (integer, bytes)
  • used_percent (float, percent)
  • inodes_free (integer, files)
  • inodes_total (integer, files)
  • inodes_used (integer, files)

Tags:

• All measurements have the following tags:
  • fstype (filesystem type)
  • path (mount point path)

Example Output:

% ./telegraf --config ~/ws/telegraf.conf --input-filter disk --test
* Plugin: disk, Collection 1
> disk,fstype=hfs,path=/ free=398407520256i,inodes_free=97267461i,inodes_total=121847806i,inodes_used=24580345i,total=499088621568i,used=100418957312i,used_percent=20.131039916242397 1453832006274071563
> disk,fstype=devfs,path=/dev free=0i,inodes_free=0i,inodes_total=628i,inodes_used=628i,total=185856i,used=185856i,used_percent=100 1453832006274137913
> disk,fstype=autofs,path=/net free=0i,inodes_free=0i,inodes_total=0i,inodes_used=0i,total=0i,used=0i,used_percent=0 1453832006274157077
> disk,fstype=autofs,path=/home free=0i,inodes_free=0i,inodes_total=0i,inodes_used=0i,total=0i,used=0i,used_percent=0 1453832006274169688

DiskIO Input Plugin

The diskio input plugin gathers metrics about disk traffic and timing.

Configuration:

# Read metrics about disk IO by device
[[inputs.diskio]]
  ## By default, telegraf will gather stats for all devices including
  ## disk partitions.
  ## Setting devices will restrict the stats to the specified devices.
  # devices = ["sda", "sdb"]
  ## Uncomment the following line if you need disk serial numbers.
  # skip_serial_number = false

Data collection is based on github.com/shirou/gopsutil. This package handles platform dependencies and converts all timing information to milliseconds.

Measurements & Fields:

• diskio
  • reads (integer, counter)
  • writes (integer, counter)
  • read_bytes (integer, bytes)
  • write_bytes (integer, bytes)
  • read_time (integer, milliseconds)
  • write_time (integer, milliseconds)
  • io_time (integer, milliseconds)
  • iops_in_progress (integer, counter) (since #2037, not yet in STABLE)

Tags:

• All measurements have the following tags:
  • name (device name)
• If configured to use serial numbers (default: disabled):
  • serial (device serial number)

Sample Queries:

Calculate percent IO utilization per disk and host:

SELECT derivative(last("io_time"),1ms) FROM "diskio" WHERE time > now() - 30m GROUP BY "host","name",time(60s)

Example Output:

% telegraf -config ~/.telegraf/telegraf.conf -input-filter diskio -test
* Plugin: inputs.diskio, Collection 1
> diskio,name=mmcblk1p2 io_time=244i,read_bytes=966656i,read_time=276i,reads=128i,write_bytes=0i,write_time=0i,writes=0i 1484916036000000000
> diskio,name=mmcblk1boot1 io_time=264i,read_bytes=90112i,read_time=264i,reads=22i,write_bytes=0i,write_time=0i,writes=0i 1484916036000000000
> diskio,name=mmcblk1boot0 io_time=212i,read_bytes=90112i,read_time=212i,reads=22i,write_bytes=0i,write_time=0i,writes=0i 1484916036000000000
> diskio,name=mmcblk0 io_time=1855380i,read_bytes=135861248i,read_time=58484i,reads=4081i,write_bytes=364068864i,write_time=7128792i,writes=18019i 1484916036000000000
> diskio,name=mmcblk0p1 io_time=1855256i,read_bytes=134915072i,read_time=58256i,reads=3958i,write_bytes=364068864i,write_time=7128792i,writes=18019i 1484916036000000000
> diskio,name=mmcblk1 io_time=384i,read_bytes=2633728i,read_time=728i,reads=323i,write_bytes=0i,write_time=0i,writes=0i 1484916036000000000
> diskio,name=mmcblk1p1 io_time=216i,read_bytes=860160i,read_time=288i,reads=106i,write_bytes=0i,write_time=0i,writes=0i 1484916036000000000