3.2

Question 1

Whats Fault tolerance used for?

Answer 1

To maintain uptime in the case of failure.

Question 2

how do we implement fault tolerance?

Answer 2

By using redundant hardware components(multiple devices, load balancing power supplies).

Question 3

Whats load balancing?

Answer 3

It’s sharing the service load across components(some servers are active and some are on standby and will activate when something goes wrong).

Question 4

Whats clustering used for?

Answer 4

If any individual server fails, the other servers will still provide that function in a cluster of servers.

Question 5

How does high availability help?

Answer 5

It’s configuration thats always on and always available for devices to never go down during a redundancy(if a firewall goes out, we replace it, HA helps during the time firewall is being replaced.) and ususally cost more.

Question 6

What does a load balancer do?

Answer 6

it is always checking on the health of the servers and if one fails, the passive server takes its place.

Question 7

Whats NIC teaming?

Answer 7

(also called Load Balancing/Fail Over: LBFO).
This provides not only aggregation of bandwidth because you’re using multiple network connections, but you would also have redundant paths. So if one path disappears, you still have a way to communicate out of that server.

Question 8

How does a NIC teaming work?

Answer 8

Even though it looks like a single adapter, it’s multiple network adapters integrated with switches (For redundancy). NCIs talk to each other and if one doesnt respond, the rest will work instead.

Question 9

What is port aggregation?

Answer 9

combining (aggregating) multiple network connections in parallel in order to increase throughput beyond what a single connection could sustain, and to provide redundancy in case one of the links should fail.

Question 10

Whats UPS?

Answer 10

(Uninterruptible Power Supply) It’s a short-term backup power for blackouts, brownouts and surges.

Question 11

What are the different kinds of UPS?

Answer 11

1. Offline/Standby UPS
2. Line-interactive UPS
3. On-line/Double-conversion UPS

Question 12

What are some of the features of UPS?

Answer 12

Auto-shutdown, additional battery capacity, outlets, phone line suppression.

Question 13

Whats a generator?

Answer 13

It’s a long-term power backup (but it requires fuel storage since it’s an engine.

Question 14

When do we use the generator and battery backup?

Answer 14

If the power is out, the generator takes some time to start, during this time we can used the battery UPS until generator is ready).

Question 15

Whats a Dual-power supply used for?

Answer 15

For redundancy (If a server supports redundant power supplies)

Question 16

What are the features of dual-power supply?

Answer 16

1. Each power supply can handle 100% of the load

2. The power suppliers are hot-swappable (replace a faulty power supply without powering down).

Question 17

Whats cold site?

Answer 17

1. No hardware(empty building)
2. no data(bring it with you)
3. no people available(Bus in your team)

Question 18

Whats warm site?

Answer 18

1. somewhere hot and cold(just enough to get going)
2. Big room with rack space (You bring the hardware)
3. Hardware is ready and waiting(you bring the software and data)

Question 19

Whats hot site?

Answer 19

1. An exact replica(Duplicate everything)
2. Stocked with hardware(constantly updated, you buy 2 of everything, am expensive recovery)
3. Applications and software are constantly updated
4. Flip a switch and everything moves

Question 20

What are the different kinds of backup?

Answer 20

1. Full
2. Differential
3. Incremental

Question 21

Whats full backup?

Answer 21

It’s a backup of everything which we usually need it first.

Question 22

Whats incremental backup?

Answer 22

It’s a backup of all files changed since the last incremental backup.

Question 23

Whats a differential backup?

Answer 23

It’s a backup of all files changed since the last full backup,

Question 24

Whats snapshot?

Answer 24

Snapshot can capture the current configuration and data of a cloud(application instances are constantly built and torn down.) and it can help to revert to known state and rollback to known configuration.

Question 25

Whats MTTR?

Answer 25

Mean time to restore(Mean time to repair)

Question 26

Whats MTBF?

Answer 26

Mean time between failures(predict the time between failures

Question 27

Whats SLA?

Answer 27

Service level agreement(contractual recovery expectations and may include penalties for not meeting certain service levels.)