Section 28: Planning for the Worst Flashcards
Redundancy
It’s basically having a backup, just in case something goes bad
Single Point of Failure
The individual elements, objects, or parts of a system that would cause the whole system to fail if they were to fail
Redundant Power Supply
Two or more supplies in a server or computer
Surge
An unexpected increase in the amount of voltage provided
Spike
A short transient in voltage that can be due to a short circuit, tripped circuit breaker, etc.
Sag
An unexpected decrease in the amount of voltage provided
Brownout
Occurs when the voltage drops low enough that it typically causes the lights to dim and the computer to shut off
Blackout
Occurs when there is a total loss of power for a prolonged period
UPS
Combines the functionality of surge protector with that of a battery backup (usually won’t last much more than 15-30 minutes)
Backup Generator
An emergency power system used when there is an outage of the regular power
Gas generator
Noisy and is the cheapest solution
Permanently installed generator
much more expensive, runs on natural gas or diesel fuel
Battery inverter generator
super quiet, virtually no user interaction
RAID
Allows the combination of multiple physical hard disks into a single logical hard disk drive that is recognized by the operating system
RAID 0
RAID 1
Provides redundancy by mirroring the data identically on another disk
RAID 5
Provides redundancy by striping data and parity data across the disk drives
RAID 10
Combination of Raid 1 and 0 (good example of a disaster tolerant raid)
Network Redundancy
Internet Connections - don’t just have this stuff going through one NIC or cables
Clustering
Two or more servers working together to perform a function
Failover Cluster
A secondary server can take over the function when the primary one fails
Load-balancing Cluster
Servers are clustered in order to share resources such as CPU, RAM, and hard disks
Redundant Site
Another place to work if one of the places you work goes down
Hot Site
A near duplicate of the original site of the organization that can be up and running within minutes
Warm Site
A site that has computers, phones, and servers but they might require some configuration before users can start working
Cold Site
A site that has tables, chairs, bathrooms, and possibly some technical items
Kinds of Backups
Full, incremental, differential
Full Backup
All of the contents of a drive are backed up
Incremental Backup
Only conducts a backup of the contents of a drive that have changes since the last full or incremental backup
Differential Backup
Only conducts a backup of the contents of a drive since the last full backup
10 Tape Rotation
Each tape is used once per day for two weeks and then the entire set is reused
Grandfather-Father-Son Rotation
Three sets of backup tapes are defined as the son (daily), the father (weekly), and the monthly (grandfather)
Towers of Hanoi Rotation
three sets of backup tapes (like the grandfather father son) that are rotated in a more complex system
Snapshot Backup
Type of backup primarily used to capture the entire operating system image including all applications and data
Disaster Recovery Planning
The development of an organized and in depth plan for problems that could affect the access of data or the organization’s building
Business Impact Analysis
identifies risks and their affect on ongoing operations
MTD
Sets the upper limit on the recovery time (maximum tolerable downtime)
RPO
How long you can be without your data
Mean Time to Repair
Measures the average time to repair something after it breaks
