# Prometheus metrics (using pg\_up)

**URL:** <https://discuss.prometheus.io/t/prometheus-metrics-using-pg-up/85>\
**Category:** PromQL\
**Created:** [March 23, 2021, 5:36pm UTC](https://discuss.prometheus.io/t/prometheus-metrics-using-pg-up/85 "2021-03-23T17:36:08Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![shawnk79](https://dub1.discourse-cdn.com/flex017/user_avatar/discuss.prometheus.io/shawnk79/32/64_2.png) [@shawnk79](https://discuss.prometheus.io/u/shawnk79)\
**Post date:** [March 23, 2021, 5:36pm UTC](https://discuss.prometheus.io/t/prometheus-metrics-using-pg-up/85/1 "2021-03-23T17:36:09Z")

</div>

I am using below query to find filesystem usage. It works good but i’d like to implement the alert on select filesystems.

( 1 - (node\_filesystem\_free\_bytes{device!~'rootfs’} / node\_filesystem\_size\_bytes{device!~'rootfs’})) \* 100 \* on ( node\_name ) group\_left pg\_up

Any idea how to do that