Disk monitoring

Disk monitoring can be done using check-disk of the official check plugin pack. To learn how to install the official check plugin pack, please refer to Using the official check plugin pack for check monitoring.

Using check-disk

In order to monitor disks using check-disk, write a command similar to the following example into the mackerel-agent.conf and restart the mackerel-agent.

In the following example, Warning occurs when the /tmp disk capacity is 10% or less, and Critical when the disk capacity is 5% or less.

[plugin.checks.disk]
command = "check-disk --path /tmp --warning 10% --critical 5%"

The options --warning and --critical can be specified by disk capacity instead of "%". Additionally, multiple --path options can be specified, in which case they are treated as OR conditions.

In the following example, the two partitions "/tmp" and "/var" are checked and if the capacity of either partition falls below 10 GB, Warning will occur. If the capacity falls below 5 GB, Critical will occur.

[plugin.checks.disk]
command = "check-disk --path /tmp --path /var --warning 10 --critical 5 --units GB"

Specifying thresholds

With check-disk, thresholds can be configured to generate alerts for the monitoring target disk using options like the following.

  • -w, --warning
    • If the available disk space or the disk ratio is less than the configured value, a Warning alert occurs
  • -c, --critical
    • If the available disk space or the disk ratio is less than the configured value, a Critical alert occurs
  • -W, --iwarning
    • If the inode ratio is less than the configured value, a Warning alert occurs
  • -K, --icritical
    • If the inode ratio is less than the configured value, a Critical alert occurs

Specifying partitions

By default, check-disk monitors all devices, but you can also specify the file system type and the device mount point to be monitored.

  • -p, --path
    • Monitor the specified device (multiple specifications possible)
  • -x, --exclude-device
    • Exclude the specified device from the monitoring targets
  • -X, --exclude-type
    • Exclude devices of the specified file system type from the monitoring targets (multiple specifications possible)
  • -N, --include-type
    • Monitor devices of the specified file system type only (multiple specifications possible)

In the following example, all devices excluding “/tmp” type are monitored.

[plugin.checks.disk]
command = '''
  check-disk                  \
    --include-type none       \
    --exclude-device /tmp     \
    --warning 10%             \
    --critical 5%
'''

For other options check out check-disk --help and README.

Source code

The check-disk source code is publicly available here:

https://github.com/mackerelio/go-check-plugins/tree/master/check-disk