CHAP 8.1 Business Continuity

Question 1

what is business continuity

Answer 1

set of related activities targeted to ensure:
- critical business functions will continue to operate despite major disruption
- ability to recover operation within short period of time after major incidents
objective is to MINIMIZE OUTAGE TIME

Question 2

impacts of downtime

Answer 2

• loss of revenue
• damaged reputation
• loss of productivity

Question 3

key elements of business continuity

Answer 3

• resilience
• recovery
• contingency

Question 4

high availability

Answer 4

• no downtime

- alw avail 24/7

Question 5

loss of availability

Answer 5

outage/downtime
types:
- planned (eg maintenance)
- unplanned (eg offline, slow response)

Question 6

common threats to availability

Answer 6

• disease
• earthquake
• fire
• cyber attack

Question 7

high availability requirements

Answer 7

• no. of users affected
• no. of external customers affected
• available budget

Question 8

HA technologies

Answer 8

• fault-tolerant & redundancy: use fault-tolerant components to improve redundancy
• network load balancing: distributes application requests among multiple nodes
• failover clustering: migrates services from one server to another when the server fails
• VM migration: moves a VM to a new host wo shutting it down

Question 9

fault-tolerant components

Answer 9

fault-tolerant components IMPROVE REDUNDANCY
eg:
- SAN STORAGE w duplicate power supply unit, nwk cabling
- disk configured w RAID support hot-swap

Question 10

RAID 0

Answer 10

• striped set
• data written across ALL disks in 64kb units (striped)
• provides performance but not fault-tolerant
• storage efficiency: 100%

Question 11

RAID 1

Answer 11

• disk mirroring
• simultaneously writes data to two volumes on two physical disks
• almost any volume can be mirrored, incl the system and boot volumes
• storage efficiency: 50%

Question 12

RAID 3

Answer 12

• striped set w dedicated parity disks
• parity data used to recover missing data if one disk is down
• parity data is written on a dedicated disk
• requires MINIMUM 3 DISKS
• storage efficiency: (n-1)*100/n (n=no. of disks)

Question 13

RAID 5

Answer 13

• striped set w distributed parity
• requires MINIMUM 3 DISKS
• storage efficiency: (n-1)*100/n (n=no. of disks)

Question 14

RAID 6

Answer 14

• striped set w dual distributed parity
• use parity to recover missing data from UP TO 2 FAILED DISKS
• require MINIMUM 4 DISKS
• storage efficiency: (n-2)*100/n (n=no. of disks)

Question 15

RAID 1+0

Answer 15

• nested RAID
• data is mirrored then striped
• require MINIMUM 4 DISKS
• storage efficiency= 50%

Question 16

network load balancing

Answer 16

• scalable HA technology
• balances traffic based on node utilization
• provides scalability as more servers can be added
• provides availability when:
  - server failure is detected
  by other servers in the cluster
  - failed server load will be automatically distributed among other servers in the cluster

Question 17

requirements to implement NLB

Answer 17

all nodes must:

• have the same configuration
• data can be stored in a central location
• data can be synchronized between servers

Question 18

failover clustering

Answer 18

• provides fault-tolerance by ensuring availability of critical services
• computers (nodes) are setup as a cluster
• requires private nwk which is shared by the cluster nodes and is used to monitor each node’s status and communicate w each other
• clustered services and resources are moved from one node to another when a node becomes inactive or fails
• cluster service can fallback after the offline node becomes active again
• usually implemented as part of a load balancing process

Question 19

when to use failover clustering?

Answer 19

• when HA is required
• scalability is not required
• application uses IP-based protocols
• client or protocol can automatically reconnect to the application

Question 20

hyper-v replica

Answer 20

• allows for host-based replication of VMs wo the need for any shared cluster components
• uses AD or certificate based authentication for security
• once VM has been replicated, it can be powered off and powered on to carry out planned or unplanned failover

Question 21

live migration

Answer 21

• moves running VMs from one physical server to another w no impact on availability for users
• pre-copies the memory of the migrating VM to the destination server
• no special configuration needed for the guest OS
• provides HA

Question 22

DHCP service HA

Answer 22

• dhcp servers share dhcp scope and lease info to ensure continuous availability
• configured using dhcp failover

Question 23

DHCP service HA failover modes

Answer 23

hot standby mode:
- secondary server will take over when primary server is unavailable

load balance mode:

• both servers dhcp clients
• requests are load balanced between servers

Question 24

cold backup site

Answer 24

• provides office space only
• takes longer to get into full operation
• least expensive

Question 25

hot site

Answer 25

• fully staffed and includes all equipment, software and communications facility
• can take over operations quickly
• most expensive

Question 26

warm site

Answer 26

• site may be installed w most of the equipment and facility preconfigured for operation
• needs time to recover and start operation