Diskio: indicate device type

[phemmer]

Proposal:

When using the diskio plugin, provide a tag which indicates what the device type is. For example, LVM PV or VG, a partitioned disk, an md-raid member, a filesystem, etc.

Current behavior:

Right now, the only provided tag is name.

Desired behavior:

A tag which indicates what the device type is. For example, LVM PV or VG, a partitioned disk, an md-raid member, a filesystem, etc.

Use case: [Why is this important (helps with prioritizing requests)]

For devices which have been sliced up (LVM PV or VG, partitioned disk, etc), the diskio plugin is going to report on both the parent device, as well as the child devices. For example, on a partitioned disk named sda, it's going to report on sda, sda1, and sda2. The metrics for sda are (mostly) just going to be the summation of the sda1 and sda2 metrics. Therefore, it would be useful to be able to filter out the parent devices when performing queries against influxdb.
Or, if you are interested in the parent devices, you could use the feature to filter out the children.