Active/Active Failover Model; Active/Passive Failover Model; Resource Model - HP StorageWorks 8000 - NAS User Manual

Active/Active Failover Model

In this model:
To facilitate file system failover, the NAS servers have full access to each other's
disk resources but do not use the shared access unless a server failure occurs.
When the failure criteria have been met, the failover system directs a NAS server
to fail over. The NAS server then takes over the IP and disk resources of the failed
server and begins serving the file systems and associated shares as if they were its
own.
Note that both NAS servers provide CIFS and NFS services.

Active/Passive Failover Model

In this model:
The active NAS server operates as in the active/active model, providing both CIFS
and NFS services to client systems. Active/passive mode is created by starting
failover packages on only one primary server and configuring the secondary
server to be the failover target in the event of a primary server failure.

Resource Model

The cluster has a shared-nothing resource model, which means each server has
exclusive access to the storage (volume groups, volumes, and shares) and network
resources (hostname, failover package names, IP addresses) that it serves. The
cluster nodes can see each others' storage and are aware of each others' packages
and IP addresses, but by agreement and design, they activate only the storage and
network addresses to which they are currently assigned. The clustering system
strictly enforces this agreement to prevent concurrent or shared access to the same
storage resources. The file system that is used for each file volume is not
distributed and does not support simultaneous shared access. The cluster quorum
server's primary job is to enforce the shared-nothing cluster policy.
HP StorageWorks NAS 8000 User's Guide
Both NAS servers provide simultaneous access to storage.
Each NAS server maintains separate file systems, CIFS shares, and NFS
exports.
The NAS servers do not provide shared access to the same volumes and file
systems simultaneously. Each NAS server functions as a separate file server.
Only one NAS server is active at a time.
The other NAS server waits in standby mode until a failover occurs.
HP NAS 8000 Concepts
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