vfs.dev.read or vfs.dev.write: bps parameter not supported

[s0r1n]

From Zabbix documentation the possible values for the second parameter for 'vfs.dev.read' or 'vfs.dev.write' are: sectors, operations, bytes, sps, ops, bps

https://www.zabbix.com/documentation/3.0/manual/config/items/itemtypes/zabbix_agent

Why is 'bps' (under Ubuntu) not supported?

$ /usr/bin/zabbix_get -s localhost -k vfs.dev.write[/dev/sda,bps]
ZBX_NOTSUPPORTED: Invalid second parameter.

$ /usr/bin/zabbix_get -s localhost -k vfs.dev.write[/dev/sdb,bps]
ZBX_NOTSUPPORTED: Invalid second parameter.

[glebs.ivanovskis]

https://www.zabbix.com/documentation/3.0/manual/appendix/items/supported_by_platform