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Unless I misunderstood something, it seems they have a single primary that handles read+write and multiple read replicas for it. It shouldn't be too difficult
by cbg0 6y ago
Unless I misunderstood something, it seems they have a single primary that handles read+write and multiple read replicas for it.
It shouldn't be too difficult given the current use of MariaDB to start using something like Galera to create a multi-master cluster and improve redundancy of the service, unless there are some non-obvious reasons why they wouldn't be doing this.
I think I also see redundant PSUs, would be neat to know if they're connected to different PDUs and if the networking is also redundant.
- lykr0n 6y agoThat's still a very common pattern if you need maximum performance, and can tolerate small periods of downtime. When designing systems, you have to accept some drawbacks. You can forgo a clustered database if you have a strong on call schedule, and redundancy built in to other parts of your infrastructure. Galera is great, but you lose some functionality with transactions and locking that could be a deal breaker. And up until MySQL 8, there were some fairly significant barriers to automation and clustering that could be a turn off for some people. Everything has it's pros and cons.
- jabberwcky 6y agoMulti-master hardly comes for free in terms of complexity or performance, you're at the mercy of latency. Either host the second master in the same building, in which case the redundancy is an illusion, or host it somewhere else in which case watch your write rate tank Asynchronous streaming to a truly redundant second site often makes more sense
- birdman3131 6y agoHow well would same city with fiber between work?