Backup and Recovery

Question 1

File backups

Answer 1

• The archive attribute
  
  • Set when a file is modified
• Full - Everything
  
  • You’ll want this one first

• Incremental
• All files changed since
the last incremental backup

• Differential
  
  • All files changed sincethe last full backup

Question 2

Incremental Backup

Answer 2

• A full backup is taken first
• Subsequent backups contain data changed since the
last full backup and last incremental backup
• These are usually smaller than the full backup

• A restoration requires the full back and all of the
incremental backups

Question 3

Differential Backup

Answer 3

• A full backup is taken first
• Subsequent backups contain data changed since the
last full backup
• These usually grow larger as data is changed

• A restoration requires the full back and the last
differential backup

Question 4

Recovery

Answer 4

• Mean time to restore (MTTR)
  
  • Mean time to repair
• Mean time between failures (MTBF)
  
  • Predict the time between failures

• Recovery may have a predefined service level
agreement (SLA)
• Contractual recovery expectations
• May include penalties for not meeting certain
service levels

Question 5

Taking snapshots

Answer 5

• The cloud is always in motion
• Application instances are constantly built and torn
down

• Snapshots can capture the current configuration and
data
• Preserve the complete state of a device, or just the
configuration

• Revert to known state
  
  • Fall back to a previous snapshot

• Rollback to known configuration
• Don’t modify the data, but use a previous
configuration

• Live boot media
• Run the operating system from removable media -
very portable!