Product Line: VERDE
Having a multi-server cluster requires a shared storage (NAS) device. All pertinent data is stored on the NAS. Database, gold image, user information, etc. In a clustered env, the only thing, by default, that is stored on the individual servers is the VERDE code. The only caveat is if CACHEIO is enabled. Then, a copy of the gold image is written to each server in the cluster. This reduces I/O and speeds up performance.
In a Clustered env, you have one Cluster Master (CM) at a time. It's the brains. It performs load balancing. It's aware of how powerful and resourceful the various servers in it's cluster are. The CM knows what server the next guest image should run on. And, most of the time, the CM runs VDI's as well (guest images).
In a normal Cluster, you have a Cluster Master Candidate. Its purpose is to backup CM as well as run VDI's. If the CM doesn't send out a heartbeat every 15 seconds, the Candidate assumes the CM is hung or dead. The Candidate takes action to take over the CM role. This activity does not affect those images running on the Candidate nor additional VDI-only servers. Users with images running on the original Cluster Master will need to log back in. But, since everyone's data is on the NAS, no one loses saved data. Users that were running on the original CM will loose what they were working on at the time of the server failure.
Yea, this is all standard fare for VERDE. All included. No additional switches or software.