Page Comparison

Levels of Redundancies

• Level 0: no redundancy
• Level 1: support manual failure detection & rerouting or recovery within a single site; expectations to complete in 30 minutes
• Level 2: support automated failure detection & rerouting 
  • within a single geographic site
  • stateless components: establish baseline measure of failed requests for a component failure within a site 
  • stateful components: establish baseline of data loss for a component failure within a site
• Level 3: support automated failover detection & rerouting 
  • across multiple sites 
  • stateless components 
    • improve on # of failed requests for component failure within a site 
    • establish baseline for failed requests for site failure 
  • stateful components 
    • improve on data loss metrics for component failure within a site 
    • establish baseline for data loss for site failure

Level 3 redundancy → Geo-Redundancy

Geo-redundancy types

active / standby 

cold standby

warm standby

hot standby

active / active