The Aurora documentation states that data is replicated six ways, across three availability zones. The Canada region (ca-central-1) offers Aurora as an option, yet only has two availability zones. How is data replication handled in regions with only two availability zones?
2
votes
2 Answers
0
votes
I was trying to answer a similar question in a training I'm giving.
The region in question no longer has only 2 AZs, but 3 official ones, which are called:
ca-central-1aca-central-1bca-central-1d
Curiously the ca-central-1c is left out, which leads me to believe there has been a sort of unofficial or stripped down AZ in place previously.
Looking at the official launch news for the third AZ they explicitly state, that for example S3 previously replicated its data across three AZs, even if only two were available.
It’s important to notice that Amazon S3 storage classes that replicate data across a minimum of three AZs, are always doing so, even when fewer than three AZs are publicly available.
So there was probably an unofficial/non-public third AZ present previously.
