Question 1024

Counting The Nines

A proposed design runs two-phase commit across a coordinator and four services, each independently available 99.9% of the time. What does that structure imply for how often a commit can succeed?

A

Adding a second coordinator replica lifts the transaction to roughly 99.999%, because participant downtime is masked by the standby

B

Every component must be reachable to commit, so availability multiplies to about 99.5% and one slow participant stalls the rest

C

Availability tracks the least available component, so the transaction stays near 99.9% no matter how many services join the commit

D

Only the coordinator's availability matters, because it can decide on behalf of participants that fail to answer the prepare message