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UPS Knowledge Series · Part 5 of 6
UPS for Servers and Networks — Rack UPS, SNMP and Automatic Shutdown
19" Rack UPS · SNMP cards · NMC · Graceful Shutdown · APC PowerChute · NUT
Server room · Data centre · Monitoring integration · PDU · Eaton IPM
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Line-Interactive UPS (bottom) in server rack with 19-inch server — Source: Wikimedia Commons (CC BY-SA)
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Rack UPS: Form Factors and Selection Criteria
For server rooms and data centres, rack-mount UPS units in 19" form factor
are the standard. They install directly in the rack and save valuable floor space.
Height is measured in rack units (U):
| Height |
Power range |
Typical models |
Application |
| 1U |
500–3000 VA |
APC SMT1500RMI2U, Effekta RM1000 |
Network rack, small server |
| 2U |
1000–6000 VA |
Eaton 5PX 3000, APC SMX3000RMI2U |
Medium-sized server room |
| 3–4U |
3000–20000 VA |
Eaton 9PX, Effekta AX series, APC SRT |
Large server room, edge DC |
| Modular (7U+) |
from 10 kVA |
Eaton 9PX Modular, APC Symmetra, Effekta M |
Data centres, critical infrastructure |
Web interface status display of a Line-Interactive UPS — Source: Wikimedia Commons (CC BY-SA)
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SNMP Cards and Network Management Cards
An SNMP card or Network Management Card (NMC) makes the
UPS network-capable. Via the network, status, battery state, load figures and alarms can be
queried — and in an emergency, servers can be automatically shut down.
| Function |
Description |
| SNMP v1/v2c/v3 |
Integration into monitoring systems (Nagios, Zabbix, PRTG, Checkmk) |
| Web interface (HTTPS) |
Browser-based configuration and status queries |
| Email alerts |
Notification on mains failure, battery alarm, overload |
| Shutdown control |
Automatic server shutdown via PowerChute/IPM/NUT |
| Data logging |
Long-term recording of voltage, current, frequency, battery status |
Automatic Graceful Shutdown: Software Comparison
| Software |
Vendor |
OS support |
Notes |
| APC PowerChute Business Edition |
Schneider Electric |
Windows, Linux, VMware |
Free, hypervisor integration, scripting |
| Eaton Intelligent Power Manager (IPM) |
Eaton |
Windows, Linux, VMware, Hyper-V |
Central management for multiple UPS, REST API |
| NUT (Network UPS Tools) |
Open Source |
Linux, *BSD, macOS, FreeNAS/TrueNAS |
Client/server architecture, vendor-agnostic, 170+ devices |
| Effekta ViewPower |
Effekta |
Windows, Linux |
Free, easy configuration |
Monitoring Integration: UPS in Nagios, Zabbix, PRTG and Checkmk
UPS units with SNMP cards integrate into any professional monitoring system.
Key SNMP OIDs for UPS (APC MIB example):
| Parameter |
APC MIB OID |
Values |
| Battery status |
1.3.6.1.4.1.318.1.1.1.2.1.1.0 |
1=normal, 2=low, 3=faulty |
| Remaining runtime (min) |
1.3.6.1.4.1.318.1.1.1.2.2.3.0 |
Timeticks / 100 |
| Battery capacity (%) |
1.3.6.1.4.1.318.1.1.1.2.2.1.0 |
Percent 0–100 |
| Mains status |
1.3.6.1.4.1.318.1.1.1.4.1.1.0 |
1=online, 2=onBattery, 3=onBypass |
500 kVA UPS system for data centres during installation — Source: Wikimedia Commons (CC BY-SA)
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PDU: Intelligent Power Distribution in the Rack
Basic PDU
Passive power strip for 19" rack. No metering, no switching.
Inexpensive, reliable.
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Metered PDU
Current metering per outlet or input.
Display and SNMP monitoring.
For capacity planning.
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Switched PDU
Remotely switchable per outlet.
Remote reboot, sequential power-on.
For remote data centre management.
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PDU in the shop: Power Distribution Units PDU.
Frequently Asked Questions: UPS for Servers and Networks
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Do I need a separate UPS for each server?
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No — a central rack UPS with sufficient VA powers all servers in the rack.
Advantage: simpler management, lower investment, less maintenance.
Disadvantage: single point of failure. Solution: two UPS (N+1) for critical environments.
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Does NUT work with Effekta UPS?
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Yes — many Effekta units use the Megatec/Q1 protocol (USB or RS232), which NUT
supports via the blazer_usb or blazer_ser driver. Always check
compatibility against the NUT Compatibility List (networkupstools.org) before purchase.
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What is the difference between USB and SNMP connection to a UPS?
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USB/RS232: direct connection, one server per UPS. Free, no network card required.
SNMP (NMC): network-based, unlimited clients can query, central monitoring, email alerts,
web interface. For server rooms with multiple servers, SNMP is the professional solution.
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More parts of the UPS Knowledge Series
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