|
Building Sun Data Redundancy |
|
|
|
|
Page 3 of 3
Uninterruptable Power Supply
An uninterruptable power supply (UPS) is a device with a built-in battery that sits between the power supply and your server(s). It protects your equipment from power outages, brownouts, sags, surges, bad harmonics, etc., which can adversely affect the performance of the system. UPSs are available in numerous configurations. A UPS that can protect a single server will cost around $250. If you have a network of servers, UPS costs can run into thousands of dollars.
There are two types of SunSystems site — the ones that have had a power problem and the ones that will have a power problem. A UPS will be one of the most important pieces of equipment you will install to help ensure the reliable operation of your system.
Standby Power Supply
There are many UPSs with varying capabilities. A "standby power supply" or "offline UPS" is not a true UPS. It won’t protect your server. This standby power supply’s power comes directly from the power line, until the power fails, then a battery-powered inverter takes over. The time required for the inverter to start providing electricity to your server varies greatly. Some servers might tolerate a standby power supply, but don’t chance it.
Hybrid UPS
A "hybrid UPS" is a device that uses a ferroresonant transformer to maintain a constant output voltage between the power source and your server, protecting against line noise. It can maintain output relying on its battery (a secondary power source) for a limited period of time. If power is not reinstated, a total outage occurs. It is questionable whether this type of device can actually respond when needed without an accompanying interruption in power. There is some debate as to whether a UPS’s ferroresonant transformer will interact with the ferroresonant transformers in your equipment, producing unexpected results. The hybrid UPS system is comparatively cheap, but, if you choose it, be sure to test it thoroughly with all of your equipment before going on-line.
True UPS
All e-commerce operators should use "true" UPS systems. While these systems are more expensive to purchase and maintain than the others we have examined thus far, this system continuously operates from an inverter with no switchover time and offers good protection from power problems.
A true UPS has internal batteries and can absorb small power surges. It continues to provide power during line sags, negates noisy power sources, and provides power for a set length of time during a power loss. It provides continuous power independent of the outside power supply. The minimum support you want from any UPS system is 30 minutes, enough to survive short outages and other power inconsistencies. Keep in mind though, as you design your server system that a true UPS generates quite a bit of heat; so don’t put it in a closed space.
Only registered users can write comments.
Please login or register.
|
Sun Documentation 
