Zabbix agent doesn't show right disk stats like vfs.dev.read and vfs.dev.write under FreeBSD.
It may takes device name like pass or ada (vfs.dev.read[ada]) while FreeBSD uses pass0 or pass1, ada0 or ada1 and this is different devices!
vfs.dev.read[ada] works, but vfs.dev.read[ada0] doesn't work. While vfs.dev.read[ada0] will be right!