High Availability; Clusters; Failover Packages - HP StorageWorks NAS 8000 - Version 1.6.X Manual

Network and Storage Planning

High Availability

The NAS 8000 dedicated storage high availability solution includes a cluster, or group, of two
NAS servers that function as a unified system. It also includes a Quorum server.
The main purpose of high-availability clusters is to provide a higher degree of storage
availability to client systems than is possible with a single server. This is accomplished by
eliminating single points of failure and providing functional redundancy. Uninterrupted
service is provided by failing over file serving capabilities (see
to a secondary server in the event of a failure in the primary server in the cluster.

Clusters

HA clusters provide a higher degree of storage availability than is possible with a single server.
This is provided by:
Note:
See the HP support web site at
Configuring and Using an HP NAS 8000 HA Cluster for more information.

Failover Packages

When a package failure is detected, the failover package is halted and fails over to another
node, provided that an eligible adoptive node is present. Each failover package and its
associated resources are monitored independently. This allows failures that are limited to a
single failover package to be handled without affecting the state of other failover packages.
The NAS solution supports two failover models:
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The NAS servers provide failover services for each other.
The Quorum server manages the NAS servers, or cluster nodes, and provides cluster
arbitration services that prevent data corruption.
Hardware component redundancy designed to eliminate single points of failure. Each
cluster consists of two NAS servers (nodes) plus one Quorum server. The Quorum server
can be shared by multiple NAS Clusters.
All storage is grouped into separate units that are given names and are accessible only by
an assigned, unique virtual IP address. These separate units of storage are referred to as
failover packages. Storage is assigned to a failover package in units of volume groups. A
failover package may have one or more volume groups assigned to it.
HP currently supports a two-node cluster for the HP NAS 8000 solution.
Active/Active (or "Dual Active") means that both cluster nodes can be serving data
simultaneously. The nodes provide failover services for each other, but can be fully
utilized at all times. This mode is achieved by configuring failover packages to run on both
cluster nodes – effectively dividing the storage between the nodes.
Active/Passive (or "Single Active") means that one node is actively serving data while the
other node is in full-time stand-by mode, becoming active only when the other node fails.
This mode can be realized by configuring all of the failover packages and storage to run on
only one node. Without any failover packages to run, the other node waits and monitors
the other node for failure.
HP StorageWorks NAS 8000 Dedicated Storage High Availability, Solution Integration Manual (SIM)
http://hp.com/support/nas8000
Failover Packages on page 14)
for a technical paper called