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by pc86
4980 days ago
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I'll be the first to admit I don't really know anything about cross-datacenter redundancy; however, I always thought that was pretty high on the list once you had SaaS products that were pulling in enough revenue to warrant full-time employees outside of the founders. What are the reasons why you would choose not to do it? Are they all financial or are there other implications? |
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As a simple example, I've seen at least a half dozen people who had issues because they thought it was as simple as throwing a mysql node into each datacenter, only to discover (much later) that the databases had become inconsistent and that failing over created bigger problems than it solved.
Similarly, I've seen complex high-availability infrastructures where the complexity of that infrastructure created more net downtime than a simpler infrastructure would've, it just went down at slightly different times.
And you really need to think about the implications of various failure modes. If you go down in the middle of a transaction, is that a problem for your application? Is it okay to roll back to data that's 3 hours old? 3 minutes? 3 seconds?
There are any number of situations where it's reasonable to say "we expect our datacenter will fail once every couple decades and when it does, we'll be down for a couple days."