Section 28 - Planning for the Worst Flashcards
How can you plan for the worst?
By conducting redundancy and disaster recovery planning
What is “redundancy”?
A term that usually refers to something that’s extra or unnecessary. In the IT world this is a great thing.
*** It is always a good idea to have backups and multiples of things - like two servers, two connections to the internet, etc. That’s why mobile phones have both wi-fi and cellular data.
When look at redundancy planning, what are you look for?
You’re looking at your networks, servers and systems to make sure that they’re fault tolerant and that they can continue to provide services 24 hours a day.
Even with redundancy planning, things still go wrong. In these situations, what comes into play?
Disaster Recovery
What is a “redundant power supply”?
An enclosure that provides two or more complete power supplies inside of one.
Most servers are going to utilize how many individual power supplies?
Two at all times
This is an example of a redundant power supply
What are some conditions that describe the various issues that can be involved with a power source?
Surges
Spikes
Sags
Brownouts
Blackouts
What is a “surge”?
There is an unexpected increase in the amount of voltage that’s being provided
*** The US power supply is 120 volts. If it jumped up to 124 that small increase would be considered a surge. If it jumped up a lot, that would be considered a spike.
What is a “spike”?
This is a short transient voltage that’s going to be due to a short circuit, a tripped circuit breaker, a power outage, or even a lightning strike.
How can you protect against a surge or a spike?
A surge protector
What is a “sag”?
Kind of like a surge, but in reverse.
Where a surge goes up, a sag is an unexpected decrease in the amount of voltage provided.
*** Typically, this is for a short duration and it won’t affect the power to your computers. When it goes for a long time, it’s known as a brownout.
What is a “brownout”?
When the voltage is reduced for a long time.
*** Usually, your lights start dimming and your computer will turn off.
What is a “blackout”?
A total loss of power for an extended period of time
A problem associated with blackouts is when power is re-established after one occurs, you get a ___ in power that occurs and can damage your computers.
spike
*** This is why surge protectors are so important
What are the different types of backup power?
- UPS
What is a UPS?
Uninterruptible Power Supply
Combines the functionality of a surge suppressor with a battery backup
These also provide line conditioning so they protect against brownouts, sags, and surges.
What is line conditioning?
Protects your machines against short duration of power going up and back down and keeps them running smoothly
*** This is helpful against things like brownouts, sags and surges.
What is “backup generator”?
Part of an emergency power system.
Used when there’s an outage of your regular power supply for the electric grid.
What are the different types of generators?
- Portable gas-engine generators
- permanently installed generators
- battery-inverter generators
How does a portable gas-engine generator work?
The least expensive type to run with gasoline (and sometimes solar power.)
*** They are noisy, high maintenance, and have to be started manually. For this reason, they’re not typically used for large server rooms.
How does a permanently installed generator work?
Generally, these run on natural gas, propane or diesel fuel.
*** These are generally connected directly to your organization’s electrical panel. They are expensive, quiet and complex to install.
How does a battery inverter generator work?
These are based on lead acid batteries.
*** They are super quiet, require little interaction and require the batteries changed out every few years. These however can’t withhold for long periods of time so often times these types of generators will be coupled with a diesel generator.
What does RAID stand for?
Redundant Array of Independent Disks
What does RAID do?
Essentially allows you to combine multiple physical hard disks into a single logical hard disk drive inside of the OS
What the different types of RAID?
RAID 0
RAID 1
RAID 5
RAID 6
RAID 10
How does RAID 0 work?
Provides data STRIPING across multiple disks and is used to increase your performance
*** Two disks working in tandem are required for RAID 0 to work