I understand it is recommended to have a private LAN for
inter-cluster communication but we are not able to do that
due to resource limitations.

We have one network interface on each node in the 2 node
SQL server cluster (no room for expansion). Each port goes
to a switch where there is other network traffic.

What is the caveat of not creating a separate LAN for
inter-cluster communication? Can it be done? Why is
the "needed"?

Thanks,
Todd

Its all about Single Point of Failure. You don't want any. Switch ports die.
Cable become unplugged. Things happen. With only one NIC, you have a Single
Point of Failure.

Do you need to create a separate LAN for cluster traffic, no. Should you
yes. Why? See above.

Cheers,

Rod

MVP - Windows Server - Clustering
http://www.nw-america.com - Clustering

<anonymous (AT) discussions (DOT) microsoft.com> wrote

Having at least 2 separate LANs (with no common hardware infrastructure) is not just a recommendation - it is essential in obtaining MS support. The solution also needs to be on the Windows Catalogue for server clusters.

Todd,

It appears that your cluster is not a certified solution. Every certified solution has a private network and a public network. You can have a cluster with one network. But is it
recommended? NO. Is it supported? NO. Are you getting high-availability? NO.

Addtional Information:
==================
A certified cluster does not consist simply of parts that individually reside on the Microsoft Hardware Compatibility List (HCL).
For example, suppose Server model S, HBA model H, storage frame F, and fibre switch W are all certified with Microsoft. This does not mean that a cluster built with
S+H+F+W is supported - and customers requiring support should not simply build a solution with these components.

Non-certified cluster solutions are not guaranteed to operate correctly. The shared disks may be visible to multiple nodes and this can lead to corruption of application
data or instability where the connection to the disks is not reliable. You can waste a lot of time by attempting to troubleshoot perceived server cluster issues that are
being caused by the cluster hardware that you are using.

Microsoft maintains two lists of certified Cluster solutions submitted by OEM's and integrators: a legacy HCL list for NT4/2000, and the Windows Server Catalog for
Clusters. The Windows Server Catalog for Clusters contains solutions for both Windows 2000 and Windows 2003, so should be consulted first when looking for recently
certified solutions.

How to locate qualified cluster solutions for Windows
http://support.microsoft.com/?id=828262

Window Server Catalog for Cluster (contains Windows 2003 and Windows 2000 solutions as well, so consult this first when looking for configurations):
http://www.microsoft.com/windows/cat...5-23e9cd3ae95b

(Legacy) Cluster HCL for NT4 and Windows 2000 Clusters:
http://www.microsoft.com/hcl

Buy a cluster solution from your vendor that is validated on the Hardware Compatibility List (HCL) or Windows Server Catalog (WSC). Make sure they are approved for
the operating system: Windows 2000 Advanced Server, Windows 2000 Datacenter Server, Windows 2003 Enterprise Edition. Make sure that you make a complete
cluster solution, instead of buying it from a component list.

NOTE: If the cluster solution is not listed on the HCL or WSC in the Cluster category, the cluster solution is considered UNSUPPORTED. However, Microsoft PSS will
offer troubleshooting tips if the customer requests them. PSS does NOT guarantee that a resolution will be found for non-HCL or non-WSC Clusters. If no resolution is
found, the incident is not refunded.

Best Regards,

Uttam Parui
Microsoft Corporation

This posting is provided "AS IS" with no warranties, and confers no rights.

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