---
type: Monitoring Guide
title: "How to Monitor RAM / Memory Usage via SNMP"
description: "Find the hrStorage RAM row, compute percent used with allocation units, set thresholds."
resource: "https://snmp-monitoring.info/monitoring/server/ram/"
tags: [monitoring]
timestamp: 2026-07-10T00:00:00Z
---

# How to Monitor RAM / Memory Usage via SNMP

Find the hrStorage RAM row, compute percent used with allocation units, set thresholds.

## Related concepts

- Up: [SNMP Server Monitoring: CPU, RAM, Disk & Uptime](/monitoring/server/index.md)

## Frequently asked questions

### What OID is memory usage in SNMP?

Use hrStorage used/size under 1.3.6.1.2.1.25.2.3.1 for the RAM row, or UCD 1.3.6.1.4.1.2021.4.6 / .5 style total/avail when present. Twin page lists details: sensors/memory.

### How do I calculate RAM % used?

(hrStorageUsed ÷ hrStorageSize) × 100 for that row. Convert to bytes with × hrStorageAllocationUnits when you need GB.

### Does SNMP show free memory?

Derive free as (size − used) × units, or use UCD avail objects when exposed.

### Why does SNMP memory differ from free?

Different accounting of cache/buffers and which pools count as “used.” Compare trends, not single-sample equality.

## Source

Concept generated from https://snmp-monitoring.info/monitoring/server/ram/ — the SNMP Monitoring vendor-neutral knowledge base. Content is limited to what that page states (no external claims added here).