4 ms·
> it sounds like they're replicating database updates asynchronously, without waiting for the updates to be acknowledged by slaves before the master allows them
by tbrock 8y ago
> it sounds like they're replicating database updates asynchronously, without waiting for the updates to be acknowledged by slaves before the master allows them to commit. Which means the data on slaves is always slightly out-of-date, and becomes more out-of-date when the slaves are partitioned from the master. Which means that promoting a slave to master will by definition lose some committed writes.
Unless you temporarily pause writes to the primary before promting a slave.
- teraflop 8y agoSure, that's fine if you're talking about planned downtime. You still lose data if there's an unexpected failure, because by the time you realize the primary is gone, it's too late; the writes have already happened and been acknowledged.