问题
What's the difference between failover and disaster recovery?
回答1:
Failover: When one machine fails, another machine (usually in the same location) takes over and resumes service
Disaster recovery: When Godzilla destroys your data center, you do have alternative locations to keep providing your service and protocols/means for the other location to know how to keep delivering the service
Depending on the particular needs of each service, disaster recovery might just be a backup tape in a safe in a different location. In other words, it's just having a defined protocol to recover from disaster. Likewise, failover might just be having a spare backup machine which makes you go to the data center for it to take over the place of the failed one, that is, having a defined protocol about what to do in case of machine failure.
Summing up, failover answers the question 'what do I do in case a single machine fails?', disaster recovery answers 'what do I do in case a disaster happens (fire, floods, war, ISP goes bankrupt, whatever)?'
High Availability Deployment Architecture
回答2:
Failover is more linked to backup procedure.
The main difference between the two, from the end client's point of view is the downtime.
- Failover is expected to have a low downtime (1 2 hours top)
- DR can have anything between 6 hours to a day or two.
The other difference is the nature of environments available after a failover or a DR.
- Failover means the end clients see nothing and can continue his activity (development or production management)
- DR should mean only production environment is back up. All development environments are down, or seriously degraded.
回答3:
Since a disaster (like 9/11) can completely destroy a datacenter, does it mean that DR is the processes of rebuilding everything for that datacenter?
来源：https://stackoverflow.com/questions/120139/failover-disaster-recovery