Hi,
A few comments below.
Robert McHugh wrote:
> So, hypothetically what would happen to an
> in-memory database if the entire database cluster
> went down? For example if power was lost to the
> database site and the UPS failed. If nothing is
> written to the disk wouldn't the whole database be
> wiped out?
Keep in mind that every node in the cluster would have to shutdown. Not just one, but the entire thing. Hopefully with redundancy that normally isn't possible.
With that said, it does write to disk. It just doesn't do it in a synchronous manner. That means that in theory if the entire cluster shutdown, then you could lose a little bit of data.
> Is there a way to create backups of a clustered
> database periodically, in case of such a
> malfunction. What would be the procedure to
> accomplish this?
You can take hot online backups with MySQL Cluster. This would only be needed in the event of a user failure (ie. drops a table and regrets it) or if the entire cluster hardware including disks died (ie. fire wipes out data center). You can read more about that at
http://dev.mysql.com/doc/mysql/en/mysql-cluster-backup.html
Harrison Fisk, Trainer and Consultant
MySQL AB, www.mysql.com