Disaster recovery strategies (backup, pilot light, warm standby) in AWS - Step-by-Step Execution

Process Flow - Disaster recovery strategies (backup, pilot light, warm standby)

Disaster Occurs

↓

Choose Recovery Strategy

↓

Backup

↓

Restore

↓

System Up and Running

↓

Monitor

This flow shows how after a disaster, you pick a recovery method: restore from backup, activate a minimal pilot light system, or switch to a warm standby environment, then monitor the system.

Execution Sample

AWS

1. Backup: Save data regularly
2. Pilot Light: Minimal system running
3. Warm Standby: Partial system ready
4. On disaster, restore or activate
5. System recovers and runs

This sequence shows the steps of each disaster recovery strategy from preparation to recovery.

Process Table

Step	Strategy	Action	System State	Next Step
1	Backup	Data backed up to storage	Backup available	Wait for disaster
2	Pilot Light	Minimal core system running	Pilot light active	Wait for disaster
3	Warm Standby	Partial system running and ready	Warm standby active	Wait for disaster
4	Disaster occurs	Trigger recovery	Primary system down	Start recovery
5	Backup	Restore data and systems	System restoring	System up
6	Pilot Light	Activate full system from pilot light	System activating	System up
7	Warm Standby	Switch traffic to warm standby	System running on standby	System up
8	All	Monitor system health	System operational	Normal operation
9	All	Recovery complete	System stable	End

💡 Recovery complete and system stable, normal operation resumed

Status Tracker

Variable	Start	After Step 3	After Step 6	Final
Backup State	No backup	Backup available	Backup available	Backup available
Pilot Light State	Off	Pilot light active	System activating	System operational
Warm Standby State	Off	Warm standby active	Warm standby active	System running on standby
System State	Primary running	Primary running	Primary down	System stable

Key Moments - 3 Insights

Why does the pilot light strategy have a minimal system running before disaster?

Because the pilot light keeps a small core system active (see execution_table step 2) so it can quickly activate full services after disaster (step 6), reducing downtime.

How is warm standby different from pilot light in system readiness?

Warm standby runs a partial system ready to take over immediately (step 3), while pilot light only runs a minimal core system and needs activation (step 6).

Why does backup strategy take longer to recover?

Backup requires restoring data and systems from storage after disaster (step 5), which takes more time than activating or switching to a running system.

Visual Quiz - 3 Questions

Look at the execution_table at step 4, what is the system state?

A Primary system down

B System operational

C Backup available

D Pilot light active

💡 Hint

Check the 'System State' column at step 4 in execution_table

At which step does the warm standby strategy switch traffic to standby?

A Step 5

B Step 3

C Step 7

D Step 6

💡 Hint

Look for 'Switch traffic to warm standby' action in execution_table

If the pilot light system was not running before disaster, how would recovery time change?

A Recovery would be faster

B Recovery would be slower

C No change in recovery time

D System would not recover

💡 Hint

Refer to key_moments about pilot light minimal system running before disaster

Concept Snapshot

Disaster recovery strategies:
- Backup: Regular data saves, restore after disaster (slowest)
- Pilot Light: Minimal system runs, activate full system on disaster (medium speed)
- Warm Standby: Partial system runs, switch traffic immediately (fastest)
Choose based on recovery time and cost needs.

Full Transcript

Disaster recovery strategies help systems recover after failures. Backup saves data regularly and restores it after disaster, which takes time. Pilot light keeps a minimal system running to quickly activate full services. Warm standby runs a partial system ready to take over immediately. After disaster, you choose a strategy to restore or switch systems, then monitor until stable. Each strategy balances cost and recovery speed differently.

Practice

1. Which disaster recovery strategy involves keeping a minimal version of your environment running to quickly scale up after a failure?

easy

A. Pilot light

B. Backup

C. Warm standby

D. Cold standby

Solution

1. Step 1: Understand pilot light strategy

   Pilot light keeps a minimal core of your environment running, like a small copy of critical systems.

2. Step 2: Compare with other strategies

   Backup stores data but requires full rebuild; warm standby runs a scaled-down version ready to take over; cold standby is offline.

3. Final Answer:

   Pilot light -> Option A

4. Quick Check:

   Minimal running core = Pilot light [OK]

Hint: Minimal running core means pilot light strategy [OK]

Common Mistakes:

• Confusing warm standby with pilot light
• Thinking backup keeps systems running
• Assuming cold standby is always active

2. Which AWS service is commonly used to create backups for disaster recovery?

easy

A. Amazon S3

B. Amazon EC2

C. AWS Lambda

D. Amazon VPC

Solution

1. Step 1: Identify backup storage service

   Amazon S3 is designed for durable, scalable storage, ideal for backups.

2. Step 2: Exclude other services

   EC2 is compute, Lambda is serverless code, VPC is networking, none are primarily for backups.

3. Final Answer:

   Amazon S3 -> Option A

4. Quick Check:

   Backup storage = Amazon S3 [OK]

Hint: Backup storage in AWS is Amazon S3 [OK]

Common Mistakes:

• Choosing EC2 as backup storage
• Confusing Lambda with storage
• Selecting VPC for backups

3. Given a warm standby setup in AWS, which of the following best describes its state before a disaster occurs?

medium

A. Fully scaled production environment running in parallel

B. Minimal core systems running, rest offline

C. No environment running, only backups stored

D. Scaled-down but fully functional environment running

Solution

1. Step 1: Understand warm standby state

   Warm standby runs a scaled-down but fully functional environment ready to take over quickly.

2. Step 2: Compare with other options

   Fully scaled parallel is active-active, minimal core is pilot light, no environment is backup only.

3. Final Answer:

   Scaled-down but fully functional environment running -> Option D

4. Quick Check:

   Warm standby = scaled-down functional environment [OK]

Hint: Warm standby runs scaled-down functional environment [OK]

Common Mistakes:

• Confusing warm standby with full production
• Mixing pilot light with warm standby
• Thinking backup means no running environment

4. You set up a pilot light disaster recovery strategy but notice recovery time is longer than expected. What is the most likely cause?

medium

A. Backups are stored in Amazon S3

B. The pilot light environment is not fully configured and requires manual scaling

C. Warm standby environment is running at full capacity

D. The primary environment is still active

Solution

1. Step 1: Analyze pilot light recovery process

   Pilot light requires scaling up minimal systems to full production, so incomplete setup delays recovery.

2. Step 2: Exclude unrelated options

   Backups in S3 are normal; warm standby running full is unrelated; primary active is normal operation.

3. Final Answer:

   The pilot light environment is not fully configured and requires manual scaling -> Option B

4. Quick Check:

   Pilot light slow recovery = incomplete setup [OK]

Hint: Incomplete pilot light setup causes slow recovery [OK]

Common Mistakes:

• Blaming backups for slow recovery
• Confusing warm standby with pilot light
• Assuming primary environment affects recovery time

5. A company wants a disaster recovery solution that balances cost and recovery speed. They want a system running at all times but at reduced capacity, ready to scale up quickly. Which strategy should they choose?

hard

A. Backup only

B. Pilot light

C. Warm standby

D. Cold standby

Solution

1. Step 1: Understand company needs

   They want a running system at reduced capacity that can scale quickly, balancing cost and speed.

2. Step 2: Match needs to strategies

   Backup only is slow recovery; pilot light is minimal core only; cold standby is offline; warm standby runs scaled-down environment ready to scale.

3. Final Answer:

   Warm standby -> Option C

4. Quick Check:

   Running reduced capacity system = Warm standby [OK]

Hint: Running reduced capacity system means warm standby [OK]

Common Mistakes:

• Choosing pilot light for running full system
• Confusing backup with standby strategies
• Selecting cold standby for fast recovery