Redundancy Flashcards
Raid 0
Striping
Not fault tolerant
Dats is striped across multiple disks to increase performance
Minimum amount of disks needed : 2
Raid 1
Mirroring
Fault tolerant
A redundant disk is created (mirror copy)
If one disk fails the other continues to operate
Only uses 2 disks
Raid 5
Striping with parity
Fault tolerant
Minimum amount of disks : 3
Data is striped across multiple disks,
a parity is also written to each disk. This allows the array to reconstruct data if one of the disks fails.
Example: you have 3 disks A, B and C
If B fails , the parity allows A and B to reconstruct the data that was on C
Raid 10
Fault tolerant
Minimum amount of disks : 2 but normally uses 4
Combines advantages of raid 1 and raid 0
Has at least 2 disks that are mirrored and then striped
Failover cluster
Aka high availability cluster
Designed so that a secondary server can take over Incase the primary fails.
Reduces the chance of a single point of failure
Example of use : two Microsoft a Domain controllers (a spare ready to go in case one fails )
Load balancing cluster
Multiple computers/servers connected together for the purposes of sharing resources such as cpu, ram, hd.
The load is literally balanced across the servers, this increases the performance
Hot site
Cold site
Warm site
Hot- up and ready to go, no configuration required (high availability HA) this is expensive but it is the only site that can facilitate (make easy) a full recovery
Warm- has the equipment may require configuration before users can work on them. May have backups that need to be restored.
This is a good option because the downtime is less than starting from scratch and it isn’t as expensive as a hot site
Cold- has tables and chairs, maybe some phones but everything else needs to be set up and configured. This is the cheap option but there is a lot of downtime. Downtime can equal lots of lost revenue (money)
Grandfather father son backup
Backups are taken daily , the newest backup is the son (usually daily )
The weekly backup is the (father)
Monthly backup (grandfather )
A son will be promoted to father at the end of the week
At the end of the month the father will become grand father
Once the father becomes the grandfather st the end of the month the old grandfather stored somewhere (off-site archive or tape)
Towers of Hanoi
Based on math,
I don’t really know much else or understand it
Business continuity plan (BCP)
Defines how a business will continue to operate if a disaster occurs
Consists of:
Business impact analysis- examination of critical vs non critical functions
Recovery time objective (RTO)- acceptable amount of time it will take to restore services
Recovery point objective (RPO)- the acceptable latency of data, or how much data is allowed to be inaccessible after a disaster
