Chapter 18 Flashcards
System resilience - Ability to maintain level of service during adverse event; or ability to return to previous state after event
Fault tolerance - Ability to suffer fault but continue to operate
High availability - Ability to quickly recover after fault
RAID
RAID 0 - Striping, no parity
RAID 1 - Mirroring, no parity
RAID 2 - Bit level striping, parity
RAID 3 - Byte level striping, parity
RAID 4 - Block level striping, parity
RAID 5 - Block level striping, interleaved parity on 1 disk
RAID 6 - Block level striping, interleaved parity on 2 disks
Parity
Used to rebuild data on new disk
Trusted recovery
Recover to a secure state after failure or fault
DB Back Up Strategies
- Electronic Vaulting - entire backups transferred to remote site
- Remote Journaling - transaction logs sent to remote site but not applied; more frequent such as hourly
- Remote Mirroring - every transaction sent to and applied to back up DB
DR plan testing
- Read-through (checklist test) - document review
- Tabletop - role play; gather team
- Walk-through - may take some physical action
- Simulation - may involve testing and interruption to non-critical business
- Parallel Test - relocate to alternate site and implement DR
- Full-interruption Test
- Lessons Learned
Alternate processing sites
- Cold site - only housing facility, no equipment or data
- Warm site - has functioning equipment but no data
- Hot site - fully functioning with data
- Mobile site - usually either cold or warm
- Cloud computing
Mutual Assistance Agreements (MAA) - with another org
DRP documents
- Executive summary
- Dept specific plans
- Tech guides for IT staff
- Checklists for DR team
- Full plan copies for critical DR team
Disaster Recovery Plan
Should have:
- Emergency response - instructions/checklists; clear criteria for activation of DRP and who has authority to declare
- Personnel and communication - people to contact
- Assessment - of the situation and DR progress
- Backup and storage strategies
- Software escrow arrangements
- Utilities - contact info
- Logistics and supplies
- Recovery and restoration - complete only when restored to primary site
Backup types
- Full backup - backup all and then turn off archive bit
- Incremental backup - back up files with archive bit on, and then turn off archive bit
- Differential backup - back up files with archive bit on, but leave archive bit on
Tape rotation strategies
- Grandfather-father-son (GFS) strategy
- Tower of Hanoi strategy
- Six Cartridge Weekly Backup strategy
Hierarchical storage mgmt (HSM) system
Recovery - bring back business processes and operations to working state
Restoration - bringing facilities and env back to workable state
