When designing failover solutions we often look at recovery time objectives (RTO) and recovery point objectives (RPO) to determine what the requirements for failover are.
RTO is the time in which a recovery from a failure should take and for most companies we work with this is under 30 minutes. Given that an average diagnosis can take 10 minutes this only leaves a further 20 minutes at a maximum to fix the service and bring it back online.
RPO is the acceptable data loss during a recovery operation. So for instance if relying solely on a backup then your RPO might be 1 hour and the backup policy should be run every hour or less to comply with this. Note though that a backup/restore method often has significant impact on the RTO.
These 2 figures often work together to determine how the service should be designed as you can’t use a traditional point in time backup to achieve an RTO of 5 minutes but it may still achieve your RPO of 15 minutes. Likewise, you might have an RPO of 30 seconds but an RTO of 1 hour meaning that data has to be as current as possible but its not too important if it takes a while to recover providing its there.
Here at VooServers we work with a number of different technologies to design services that meet any RTO or RPO that is defined. We have a proven track record of delivering services across multiple sites with an RTO as low as 2 minutes and an RPO as low as 10 seconds.
By Matt Parkinson on October 23rd, 2015