Telegraf diskio collection stats on USB drive

Hi there,

I am having a slight issue with telegraf gathering diskio stats on a USB drive (device SDA), the statistics it collects look a bit too static. I say this because I have moved the influxdb storage area to this device and the disk i/o requests, disk i/o bytes and disk i/o time do not seem to be moving.

I have changed the devices line in telegraf.conf to look like this
devices = ["sda", "mmcblk0p1", "mmcblk0p2"]

It has picked up the SDA device, it just seems the number are incorrect. I am running this on a Raspberry Pi 4,.

Any advice would be welcome.