[Mediawiki-l] Mediawiki clusters

[Domas Mituzas]

Hello,

> I thought Wikimedia uses MySQL replication, not clustering.  MySQL
> clustering uses main memory to store tables.  Somehow I don't think  
> the
> Wikimedia servers have that much memory.

You're slightly wrong. We have enough memory to store our mysql core  
database in memory.

> BTW, MySQL 5.1 will finally
> support disk-based clustering.

Yes, for non-indexed data.

> Even then, there is still the issue of
> FULLTEXT indexes in cluster mode.  Does the cluster storage engine  
> support
> FULLTEXT indexes?

We don't use FULLTEXT indexes on live site anyway. It's pure InnoDB,  
and search is offloaded to Lucene.

Anyway, Cluster is designed to handle zillions of small transactions  
per second without data loss, it could work as a solution for session  
storage (and it is used that way on several biggish sites).

On the other hand, our access pattern would not like distributed  
database that much as there're quite a lot of batch reads.
We already solve the 'clustering' by simply having replicated sets of  
database nodes working with different workloads / patterns if needed.
We're quite happy with current setup, I guess ;-)

Domas