Question

I ve got a Java web service backed by MySQL + EC2 + EBS. For data integrity I ve looked into DRBD, MySQL cluster etc. but wonder if there isn t a simpler solution. I don t need high availability (can handle downtime)

There are only a few operations whose data I need to preserve -- creating an account, changing password, purchase receipt. The majority of the data I can afford to recover from a stale backup.

What I am thinking is that I could pipe selected INSERT/UPDATE commands to storage (S3, SimpleDB for instance) and when required (when the db blows up) replay these commands from the point of last backup. And wouldn t it be neat if this functionality was implemented in the JDBC driver itself.

Is this too silly to work, or am I missing another obvious and robust solution?

Answer 1

Have you looked into moving your MySQL into Amazon Web Services as well? You can use Amazon Relational Database Service (RDS). Also see MySQL Enterprise Support.

Answer 2

You always have a window where total loss of a server and associated file storage will result in some amount of lost data.

When I ran a modestly busy SaaS solution in AWS, I had a MySQL Master running on a large instance and a MySQL Slave running on a small instance in a different availability zone. The replication lag was typically no more than 2 seconds, though a surge in traffic could take that up to a minute or two.

If you can t afford losing 5 minutes of data, I would suggest running a Master/Slave setup over rolling your own recovery mechanism. If you do roll your own, ensure the "stale" backups and the logged/journaled critical data are in a different availability zone. AWS has lost entire zones before.

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