What exactly do you want to know?
Whether its possible to run drupal in a cluster?
MySQL now have their cluster product which, if you can get it setup (its not that easy) works well: http://www.mysql.com/products/database/cluster/
Not sure if drupal can deal with multiple databases in the old mysql-"cluster" approach using replication (i.e. you would need to modify the database connection object to detect which sql server to use - if one fails use another and switch master to slave - dodgy at the best of times though - particularly when the dead server starts up)
The only other issue of clustering is file writing. Drupal doesnt do too much of that. My approach would be to write a rsync cron (or launchd on a mac - monitoring the folder(s)) on your boxes that syncs up the fileuploads folder on each of the boxes. Thats a easy enough way.
If you are interested in running drupal (or anything for that matter) in a clustered LAMP enviroment, you may want to look at http://linuxha.net/
We are using LinuxHA with much success, although if you don't know linux very well, you will most likely have difficulty setting up the cluster even with those helpful tools.
In case you aren't familiar with LinuxHA, it helps you setup clustered servers by taking care of the really nasty configurations, like configuring DRBD (replicates data over the network as it is written to disk). It also provides monitors that will failover to another server in case a service, ethernet link, or server goes down.
Comments
what about them exactly?
What exactly do you want to know?
Whether its possible to run drupal in a cluster?
MySQL now have their cluster product which, if you can get it setup (its not that easy) works well: http://www.mysql.com/products/database/cluster/
Not sure if drupal can deal with multiple databases in the old mysql-"cluster" approach using replication (i.e. you would need to modify the database connection object to detect which sql server to use - if one fails use another and switch master to slave - dodgy at the best of times though - particularly when the dead server starts up)
The only other issue of clustering is file writing. Drupal doesnt do too much of that. My approach would be to write a rsync cron (or launchd on a mac - monitoring the folder(s)) on your boxes that syncs up the fileuploads folder on each of the boxes. Thats a easy enough way.
hth. Im sure there are some bits on drupal forums of someone already doing this. take a look around. here are some threads to start you off:
http://drupal.org/node/23289
http://drupal.org/node/3530
http://drupal.org/node/52087
will
Drupal Works Fine with Clustered LAMP Servers
If you are interested in running drupal (or anything for that matter) in a clustered LAMP enviroment, you may want to look at http://linuxha.net/
We are using LinuxHA with much success, although if you don't know linux very well, you will most likely have difficulty setting up the cluster even with those helpful tools.
In case you aren't familiar with LinuxHA, it helps you setup clustered servers by taking care of the really nasty configurations, like configuring DRBD (replicates data over the network as it is written to disk). It also provides monitors that will failover to another server in case a service, ethernet link, or server goes down.