New to cluster - a few questions

I am new to setting up a xtradb cluster - I have a few questions someone may be able to answer.

  • Does the server id in the my.cnf have to be unique for each cluster member? There is an example in the percona documentation that does this, but since this is not mytsql replication why or is this really needed?

  • I am installing on ubuntu 11.10 using the deb files. It wants to install the database in /var/lib/mysql. I am running this on standardized VMs on an internal cloud and that file system does not have enough space to hold any database components. I want to install it in /mnt/var/lib. Is there any way to customize install location when using the percona deb files? I tried dong a symbolic link from /var/lib/mysql to /mnt/var/lib/mysql but it does some funky things on install so I prefer to not do that. I would use the binary tar ball - but it depends on /usr/ which does not seem to be available on the ubuntu distribution.

1 - wsrep_cluster_name should be identical on all nodes, wsrep_node_name should be different on all nodes; wsrep has nothing to do (99% sure on this) with server-id
2 - install normally from the .deb packages, after install finishes, stop the server, move the /var/lib/mysql directory to desired location, double-check permissions, change the datadir variable in my.cnf to match new location, start server -> you’re done.