Hi all,

My company currently runs a high-traffic personal ad site. There are many many writes on the database (avg 3000/sec during non-peak times) and many many reads (avg an additional 2000/sec during non-peak times). Currently we're doing replication with 1 high-powered master for writes, and 1 high-powered slave for reads.

MySQL Cluster seems like a good solution for us, as we have machines with big enough RAM so the entirety of our database is already in RAM.

The only unresolved issue is this: What *exactly* is written to disk? Just the logs? If so, does that mean that the entire database, including structure and data, resides ONLY in RAM? So if all the nodes in a group go down, you've lost ALL your data?

This goes along with "can you take a snapshot of the data in a cluster?" And more specifically, "how are backups done?" It says hot backups are possible; does that mean something like mysqldump, or a tool that actually takes a snapshot of all the databases without locking all the tables for the length of time it takes to dump all the data?

Sincerely,