Ask HN: Does AWS EBS have contradictory availability and durability guarantees?

2 points

9 years ago

I'm going over AWS EBS product pages.

* EBS provides an availability guarantee of 99.999% (https://aws.amazon.com/ebs).

* EBS provides a durability guarantee of 99.8-99.9% (https://aws.amazon.com/ebs/details/#AvailabilityandDurability).

I don't follow how these two numbers add up however. If you're losing data %0.1-0.2 of the time, how can you provide availability guarantees that are 99.999%?

Is this because one of the guarantees is dated? Or does AWS consider available as "hey, we lost your data but you can still access EBS"? (doubt it)

I'm asking because I was reading this post (goo.gl/eNhxaj) on HA and Disaster Recovery in Citus Cloud. I thought the author made a mistake in the second or third paragraph, but found that the links actually said the same things.

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