Which if the services could spread across Multi-AZ (chose 2 correct answers)

A. EC2 B. ELB C. RDS D. Dynamo DB E. EBS

The correct answers are said to be B and C. First, the grammar is poor. Second, you can “enable cross-zone load balancing” for ELB and “provision a Multi-AZ DB Instance” RDS, and for DynamoDB “The service runs across Amazon’s proven, high-availability data centers. The service replicates data across three facilities in an AWS Region to provide fault tolerance in the event of a server failure or Availability Zone outage.” B,C, and D are all available Multi-AZ. If the question were what services are optionally Multi-AZ then the answer would be B and C but that is not how the question is worded.

You have created a Route 53 latency record set from your domain to a machine in Singapore and a similar record to a machine in Oregon. When a user located in India visits your domain he will be routed to:

A. Singapore B. Oregon C. Depends on the load on each machine D. Both, because 2 requests are made, 1 to each machine

The answer given is A which I believe is a poor answer because it assumes that the latency between India and Singapore will be the lowest. While this may often be the case it is not guaranteed and makes for a poor test question because there is additional information needed to make an accurate answer.

Be wary of the sample questions that are available when studying for the Solutions Architect Certification. I’ve come across some where the answers were out of date or used to be correct and the others were just made up questions that almost make sense but aren’t how worded precisely enough to give a proper answer.

By and large finding the sample questions is helpful, but don’t take all of them as truth and look through the documents to verify the answers.

I made my first trip to the San Francisco AWS Loft and definitely learned a lot. I attended the Continuous Delivery and Continuous Integration Day and was introduced to a lot of the build and deployment strategies involved in cloud applications.

The number of attendees was surprising. The entire loft space was filled with I’m guessing around 100 people. Definitely a great idea on the part of AWS to hold sessions like this. I’m pretty amazed at the size of the ecosystem and I’m sure it’s nothing compared to re:Invent.

RDS Failover

Our reporting engine is likely to point at a Read Replica of our database so we wondered what happens when the instance fails. Do we have to detect the failure? Do we have to manually find a new instance?

Here’s what I found:

The failover mechanism automatically changes the DNS record of the DB instance to point to the standby DB instance. As a result, you will need to re-establish any existing connections to your DB instance.

This seems to imply that while you may need to reconnect, you don’t have to reconfigure the connection. This also seems to be referencing the primary instance, but I would assume it applies to Read Replicas but I would like to verify with an RDS expert.