---
title: "Prometheus metrics thresholds"
slug: "prometheus-metrics-thresholds-v6-5"
updated: 2026-01-21T08:54:55Z
published: 2026-01-21T08:54:55Z
canonical: "support.appgate.com/prometheus-metrics-thresholds-v6-5"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://support.appgate.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Prometheus metrics thresholds

There are a few metrics where it is possible to set some default thresholds which should apply to most use cases.

| Reference | Metric | Note | Measure | External Trigger Level Appgate SDP Trigger Level | Limit Effect | Cause | Possible Action |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Warning | Error |
| A | apn_active_connections / apn_active_connections_max*100 | This is a Linux limit | % | 80% | 90% | Users connections will be dropped | Too many TCP connections (users and hosts) | Increase the number of allowed connections or reduce the number of protected hosts |
| B | avg_over_time (apn_cpu_usage_percent [10m]) | This is already a 15sec average | % time averaged over 10 minutes | 85% | 95% | Machine will slow down | Multiple | Diagnose the cause and fix, or Increase the number of vCPU |
| C | apn_disk | This is the whole disk | % | 80% | 90% | Various | Database size, Logs, Image files | Add a bigger disk |
| D | apn_disk_partition_statistic {measure="percent", func=~".*ctr.*", path="/mnt/data"} | Database is in /data so this mainly affects Controllers | % | 80% | 90% | Controllers can't sync | Database size too large | Add a bigger disk |
| E | avg_over_time (apn_memory {measure="percent"} [5m]) | High concurrency of users mainly affects Gateways | % time averaged over 5 minutes | 75% | 90% | Auto suspend GW or system failure (if reaching 100%) | Too many events or rules in Gateways | Add more RAM |
| F | gw_sessiond_heap {measure="used"} / ignoring (measure) gw_sessiond_heap {measure="max"}*100 | Used for event handling by sessiond mainly affects Gateways | % | 70% | 85% | Auto suspend GW | Too many events to handle | Add another Gateway |
| G | gw_vpn_sessions | This is very affected by the number of rules each user has been assigned | number | 4000 | 8000 | Auto suspend GW | Too many users to handle | Add another Gateway |
| H | gw_event_queue_size {measure="current"} / gw_event_queue_size {measure="length"}*100 | {measure=length) has the value 15k, 30k, 50k,100k depending on the Appliance specification. | number | 50% | 70% | Auto suspend GW | Too many events to handle | Add another Gateway |
| I | (ctr_ip_pool {usage="current",name=~".*v4"}+ignoring (usage) ctr_ip_pool {usage="reserved",name=~".*v4"}) / ignoring (usage) ctr_ip_pool {usage="total",name=~".*v4"}*100 | This calculates the % of IPv4 addresses used. | % | 75% | 90% | Health: Failed to allocate IP from pool | IP pool too small | Add another IP pool |
| J | ctr_license {type="users", measure="used"} / ignoring (measure) ctr_license {type="users", measure="entitled"}*100 | This calculates the % of "users" licenses used. | % | 85% | 95% | Health: There are more X than your license allows. | Insufficient licenses | Purchase additional licenses |
| K | ctr_client_authentication {measure="average_time"} + ctr_client_authorization {measure="average_time"} | The average time for a standard user to sign in to the Controller | mS | 2000 | 5000 | User sign in times out | Multiple | Diagnose the cause and fix, focus on external calls/scripts |
| L | gw_session_event_timing {measure="accumulated" / ignoring(measure) gw_session_event_count | The long term average execution time per event type | mS | 2000 | 5000 | Users experience slow response times | Multiple | Diagnose the cause and fix, focus on external calls/scripts |
| M | apn_certificate_days_remaining | Days remaining until certificate expiration per certificate type | days | 30 | 0 | Lost connection (different depending on certificate type) | Certificate expiring | Renew the certificate during calm hours to avoid interruptions (Appliance certificate is renewed automatically 1 day before expiry) |

Appgate SDP (Software Defined Perimeter) is a security solution that provides secure access to resources based on user identity and context, leveraging a zero trust security model.

An appliance that acts as an enforcement point, controlling user access to protected resources.

The virtual or physical instance on which the system is running. Each appliance is a stateless, configurable machine that can operate as a single function or a combination of functions.

The Controller is the central management appliance in the Appgate ZTNA system, responsible for user authentication, policy distribution, and overall system administration.