Server Power & UPS — 40 Frequently Asked Questions
Real questions enterprise IT engineers ask about Server Power & UPS, with practical answers from Pro Disk Engineering. Questions sourced from Server Fault and Network Engineering Stack Exchange under CC BY-SA — see source links per question. Answers are original Pro Disk Network content with links to our buying guides and product catalog.
What is this very short power cable called?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (249 votes · 34,373 views) ›
ipmitool - can't find /dev/ipmi0 or /dev/ipmidev/0
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
BMC access: ipmitool -H <ip> -U admin -P <pw> chassis status for remote IPMI. For Dell iDRAC, HPE iLO, Lenovo IMM/XCC, Supermicro IPMI — all expose Redfish REST API as the modern alternative.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (55 votes · 205,873 views) ›
Smell of rotten eggs in the server room
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
SMART monitoring: alert on attributes 187 (reported uncorrectable errors), 197 (current pending sector count), and 198 (offline uncorrectable count). Non-zero values typically indicate 30-90 days of remaining service life.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (99 votes · 28,702 views) ›
Does a 500 watt power supply always use 500 watts of electricity?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (42 votes · 122,932 views) ›
How do servers with redundant power supplies balance consumption?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (42 votes · 45,224 views) ›
How do I permanently disable Linux's console screen saver, system-wide?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (43 votes · 41,789 views) ›
Why do we still use power supplies on datacenter servers?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (56 votes · 13,554 views) ›
What are the pros and cons of having your own UPS attached to your own server hosted in a data center?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (51 votes · 17,991 views) ›
Assessing equipment damage following a lightning strike - Should I have planned more?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (56 votes · 7,717 views) ›
Does CPU power management affect server performance?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (43 votes · 28,836 views) ›
Is UPS worthwhile for non-production equipment?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (56 votes · 2,511 views) ›
PDU wiring - is this normal (or even safe)?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (51 votes · 4,593 views) ›
Change the UPS battery while it's powered on?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
SMART monitoring: alert on attributes 187 (reported uncorrectable errors), 197 (current pending sector count), and 198 (offline uncorrectable count). Non-zero values typically indicate 30-90 days of remaining service life.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (17 votes · 66,336 views) ›
UPS and power strip interactions?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (35 votes · 26,796 views) ›
What is the lifespan of an typical UPS battery?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (17 votes · 61,048 views) ›
How can I determine the power demand of an HP server's power supply under load?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (13 votes · 47,257 views) ›
Best practices for power cabling racks in DC
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (25 votes · 15,669 views) ›
Replace a UPS battery or buy a new UPS?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (19 votes · 21,902 views) ›
How to wake a server after UPS Shuts it down when Mains power is restored?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (18 votes · 23,860 views) ›
Testing a UPS by unplugging it from the wall
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (19 votes · 20,395 views) ›
What is the difference between a PDU and a power strip (both 120V, 15A)?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
SMART monitoring: alert on attributes 187 (reported uncorrectable errors), 197 (current pending sector count), and 198 (offline uncorrectable count). Non-zero values typically indicate 30-90 days of remaining service life.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (16 votes · 25,289 views) ›
How does a 3-Phase UPS distribute power?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
SMART monitoring: alert on attributes 187 (reported uncorrectable errors), 197 (current pending sector count), and 198 (offline uncorrectable count). Non-zero values typically indicate 30-90 days of remaining service life.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (18 votes · 12,701 views) ›
Plugging in a server rack with UPSes into a room that has its own UPS backup issues
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (19 votes · 4,107 views) ›
Is it safe to use a UPS designed for desktop PCs to power a server?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (17 votes · 5,899 views) ›
Power Usage via IPMI or BIOS or?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
BMC access: ipmitool -H <ip> -U admin -P <pw> chassis status for remote IPMI. For Dell iDRAC, HPE iLO, Lenovo IMM/XCC, Supermicro IPMI — all expose Redfish REST API as the modern alternative.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (5 votes · 29,626 views) ›
How to step down voltage from 208V to 110V
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (9 votes · 21,165 views) ›
Can Running a Server's Redundant PSU on Different Circuits Damage It?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (17 votes · 4,061 views) ›
How can I calculate if a UPS is sufficient for my requirements?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (10 votes · 10,274 views) ›
Proper Sizing for PDU's/Power in Rack
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (10 votes · 9,277 views) ›
Maxing out both PDUs in a rack with redundant power
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Source of PDU De-Rating?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Power Cables Required to Switch from 120v to 240v for Dell Poweredge Servers
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Can I hot-swap a 2-PSU server from 120 to 240 volts?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
Linux memory accounting: RSS = physical RAM in use, VIRT = virtual address space (includes mapped files), PSS = proportional shared pages. The "available" column in free already accounts for reclaimable cache — use that as your real free-RAM number.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Original question on Server Fault (10 votes · 1,362 views) ›
Redundant Power Supply Sloshing (If sloshing is the right word)
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Is there a solution against short power outages except UPS?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
UPS sizing: 5-15 min runtime with generator backup, 30-60 min for sites without. Online double-conversion UPS for production workloads. Replace RBC batteries every 3-5 years. Monitor health via SNMP.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Is it possible to use mixed 110V / 208V power on a single server with dual power supplies?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
AP8941 PDU frozen, how to reset management interface?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Is it safe to remove power from a linux computer in run level 0?
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Things to consider when buying PDUs
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Using Y split cables to connect two servers to a single PDU receptacle
Power equipment questions usually involve PSU sizing, redundancy, or UPS runtime.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships server PSUs, rack PDUs, and UPS from APC, CyberPower, Tripp Lite, Eaton. Power buying guide · Power catalog
Have a question we did not answer?
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