Large NDB Install?

[Elias Lutfallah]

Hi. I have been using mysql for years, but have not as yet tried NDB clustering.

I am considering moving my db to an NDB cluster. Currently it is in a single-server InnoDB configuration. The database currently takes up about 1.2G on disk and will only get bigger over time. I have been considering using the following setup for data nodes:

6 data nodes
12GB memory each
2 replicas

By the rough estimate formula this should give me ~32G for my db. The system will eventually have 100+ databases with the same table structure - different data. One db for each customer.

Speed is equally important as HA to me. If the db isn't snappy, no one will use it in the first place at which point HA doesn't matter.

My questions are,

1. Has anyone tried a cluster of this size? Pros and cons?

2. Is is better to set up 3 groups of 2 data nodes, or 2 groups of 3 data nodes?

3. Would I be better off using 12 data nodes w/6GB memory each?

4. If I use 3 replicas instead of 2, I would get ~21G for my db. What exactly does
having more replicas get me? Is it higher availability, or better speed?

5. Is there an estimated GA release date for the data on disk option? The ability to store non-indexed data on disk seems like an ideal situation for me. If I understand it correctly, for some tables it can make the difference between 400M in memory vs. ~200K (50,000 8K rows vs. 50,000 35b rows).

Thanks in advance for any answers,

Eli