Zabbix has a log of built-in support to monitor diskspace on servers. But I'm not always interested in triggers that fire on a certain amount or percentage of free space defined in a template. For some filesystems, it may be perfectly normal to be at 90% usage and remain stable there.
What does interest me more is the amount by which disk usage increases in a short timespan, and Zabbix does have the functionality to cater for this. For example:
{Template OS Linux:vfs.fs.size[{#FSNAME},pfree].last(0,3600)}- {Template OS Linux:vfs.fs.size[{#FSNAME},pfree].last(0)}>10
In the discovery rules for your template will alert you to any increase of more than 10% in one hour.
Happy monitoring :-)