telegraf/plugins/inputs/disk

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 wikipedia - df for more details.

Global configuration options

In addition to the plugin-specific configuration settings, plugins support additional global and plugin configuration settings. These settings are used to modify metrics, tags, and field or create aliases and configure ordering, etc. See the CONFIGURATION.md for more details.

Configuration

# Read metrics about disk usage by mount point
[[inputs.disk]]
  ## By default stats will be gathered for all mount points.
  ## Set mount_points will restrict the stats to only the specified mount points.
  # mount_points = ["/"]

  ## Ignore mount points by filesystem type.
  ignore_fs = ["tmpfs", "devtmpfs", "devfs", "iso9660", "overlay", "aufs", "squashfs"]

  ## Ignore mount points by mount options.
  ## The 'mount' command reports options of all mounts in parathesis.
  ## Bind mounts can be ignored with the special 'bind' option.
  # ignore_mount_opts = []

Docker container

To monitor the Docker engine host from within a container you will need to mount the host's filesystem into the container and set the HOST_PROC environment variable to the location of the /proc filesystem. If desired, you can also set the HOST_MOUNT_PREFIX environment variable to the prefix containing the /proc directory, when present this variable is stripped from the reported path tag.

docker run -v /:/hostfs:ro -e HOST_MOUNT_PREFIX=/hostfs -e HOST_PROC=/hostfs/proc telegraf

Metrics

• disk
  • tags:
    • fstype (filesystem type)
    • device (device file)
    • path (mount point path)
    • mode (whether the mount is rw or ro)
    • label (devicemapper labels, only if present)
  • fields:
    • 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)

Troubleshooting

On Linux, the list of disks is taken from the /proc/self/mounts file and a statfs call is made on the second column. If any expected filesystems are missing ensure that the telegraf user can read these files:

$ sudo -u telegraf cat /proc/self/mounts | grep sda2
/dev/sda2 /home ext4 rw,relatime,data=ordered 0 0
$ sudo -u telegraf stat /home

It may be desired to use POSIX ACLs to provide additional access:

sudo setfacl -R -m u:telegraf:X /var/lib/docker/volumes/

Example Output

disk,fstype=hfs,mode=ro,path=/ free=398407520256i,inodes_free=97267461i,inodes_total=121847806i,inodes_used=24580345i,total=499088621568i,used=100418957312i,used_percent=20.131039916242397 1453832006274071563
disk,fstype=devfs,mode=rw,path=/dev free=0i,inodes_free=0i,inodes_total=628i,inodes_used=628i,total=185856i,used=185856i,used_percent=100 1453832006274137913
disk,fstype=autofs,mode=rw,path=/net free=0i,inodes_free=0i,inodes_total=0i,inodes_used=0i,total=0i,used=0i,used_percent=0 1453832006274157077
disk,fstype=autofs,mode=rw,path=/home free=0i,inodes_free=0i,inodes_total=0i,inodes_used=0i,total=0i,used=0i,used_percent=0 1453832006274169688
disk,device=dm-1,fstype=xfs,label=lvg-lv,mode=rw,path=/mnt inodes_free=8388605i,inodes_used=3i,total=17112760320i,free=16959598592i,used=153161728i,used_percent=0.8950147441789215,inodes_total=8388608i 1677001387000000000