Always available web services are WS that do not have a single point of failure. This includes the loadbalancer, database, and even the data center.
Grouper should be conducive to always available web services.
The plan is to allow readonly database replication to an off site database, and have a Grouper WS application server which runs in readonly mode against that database. Then a protocol needs to be designed and dcoumented that shows how clients should interact with the multiple WS servers. This protocol should be implemented in the Grouper client. Note that there might not be consistency between the read/write and readonly depending on how the database replication is implemented.
WS client failover protocol
Configure a read/write and a readonly URL.
Identify a primary and a secondary URL (note that if there are non-readonly queries, then the readwrite should probably be the primary URL). Or the client could round robin
Try