HP NAS 4000s, Administration Manual, Page: 23 / 246

System Overview
23 NAS 4000s and 9000s Administration Guide
NAS Server as a Clustered Pair
In the clustered configuration, two NAS devices are linked via a private network and have
access to shared storage as illustrated in
Figure 2 . In clustered deployments, it is recommended
that each NAS device be attached to the SAN via a pair of fiber channel HBAs. Dual HBAs per
NAS device is recommended but not required for cluster deployments, since dual HBAs allow
for path failure without causing node failover in the cluster.
For the NAS server, cluster setup requires at least three LUNs. One LUN is required for the
quorum disk and two LUNs are required for data disks. Individual data disks specific to each
node are required for the proper setup of file sharing where both nodes participate in
file-sharing activities. Clustered NAS systems have the ability to provide redundant
active/active access to file shares on disk. However, as with all Microsoft-based clusters, the
unit of ownership among nodes is at the disk level. Therefore, individual fileshares can be
accessed by only one node at a time based on which node owns the disk.
Figure 2: NAS server as a clustered pair of devices
Multi Node Support Beyond Two Nodes
The NAS 4000s and 9000s devices may be deployed in multi node clustering beyond two
nodes. Refer to the associated Storage Array documentation to determine the number of nodes
supported by the array under Windows Storage Server 2003. While the discussion presented in
this guide addresses only two nodes, additional nodes may be added into the cluster.
Considerations for additional fiber path connections and the private network should be made.
In the case of the private network, a hub or switch is required since the cross over cable is no
longer applicable.
Connecting NAS Servers to the Network
The NAS server can be connected to the network as a single device or as a clustered pair.
Cluster Node A
Node A
HBA 1
Private Network
Node A
HBA 2
Node B
HBA 2
Cluster Node B
Node B
HBA 1
SAN Switch
SAN Switch
Storage Area Network
Cluster
Quorum
Mirrorset
LUN 1
Data RAID set
Node A
LUN 2
Data RAID set
Node B
LUN 3
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