PSS ID Number: 327831
Article Last Modified on 4/7/2004
The information in this article applies to:
- Microsoft Windows 2000 Advanced Server
This article was previously published under Q327831
SUMMARY
This article describes support for a single server cluster that is connected to multiple storage units.
Microsoft qualifies a server cluster and includes it on the Microsoft Hardware Compatibility List (HCL) if the cluster uses small computer system interface (SCSI) technology, Fiber Channel technology, and Switched Fabric technology. There are many examples of such complete configurations on the HCL. However, the HCL includes only single configurations that contain a set of cluster nodes with a single storage controller.
Storage Area Networks (SANs) that use Switched Fabric technologies offer storage consolidation and storage as a utility. In this type of environment, the storage infrastructure may contain different storage controller devices with different characteristics or guarantees or may increase over time and include storage controllers from various vendors or suppliers.
MORE INFORMATION
Microsoft supports clusters that are attached to multiple storage controller devices that may be supplied by different vendors. For the complete configuration to be considered a qualified configuration and, therefore, supported by Microsoft, each combination of nodes and storage controller must appear as a complete configuration on the Cluster HCL.
NOTE: For Microsoft to support this configuration from end to end, all the storage vendors must also support the complete configuration. Microsoft cannot support the end-to-end configuration without cooperation and support from the storage vendors. To make sure that you deploy a supportable configuration, contact the vendors for all major storage components.
Supported Configuration Example
Cluster/RAID System
- Storage subsystem SD1
- Storage subsystem SD2
Cluster HCL
- Two-node advanced server cluster AS1
- Server S1
- Server S2
- Storage subsystem SD1
- Two-node advanced server cluster AS2
- Server S1
- Server S2
- Storage subsystem SD2
In this case, both the AS1 and AS2 on the HCL contain the same cluster configuration with the same nodes but with different storage units. A cluster of S1 and S2 can be attached to a SAN that contains both storage controller devices SD1 and SD2. The cluster is a qualified and supported configuration, and it can be configured to access and use storage from both storage units.
This article describes support for a single cluster that is connected to multiple storage units. If multiple clusters are attached to the SAN and you intend to share a single storage unit across multiple clusters, the storage unit must also be on the Cluster/Multi-cluster HCL list.
For additional information about sharing a storage unit between multiple clusters, click the article number below to view the article in the Microsoft Knowledge Base:
304415 Support for Multiple Clusters Attached to the Same SAN Device
For additional information about the HCL and server clusters, click the following article number to view the article in the Microsoft Knowledge Base:
309395 The Microsoft support policy for server clusters, the Hardware Compatibility List, and the Windows Server Catalog
Other issues to consider when you deal with a single cluster that is attached to multiple SANs include the following:
- Zoning and Masking
- Microsoft strongly recommends that you put different storage units into different zones.
- Host Bus Adapters (HBAs)
- HBA driver and firmware versions are very important in cluster configurations. Storage vendors qualify configurations with specific versions of drivers and firmware, and these are listed on the Cluster HCL. Microsoft and the storage vendors support only the configurations that match their tested driver-and-firmware combinations. If you have multiple storage units that are attached through a single set of HBAs, make sure that the driver/firmware combinations are supported for all the storage configurations.
- If you use storage units from multiple vendors, you may have to use different sets of HBAs for accessing different vendors' storage units to make sure that the correct adapters and correct driver and firmware versions are used for a supported end-to-end solution. In this case, you MUST configure each adapter and storage pair in a different zone to isolate the different HBAs.
NOTE: Windows cannot load different driver versions for the same type of adapter. If your computer has multiple adapters that are exactly the same, they MUST all use the same driver and firmware combinations.
- Multi-path Issues
- Enterprise storage configurations have multiple paths to the storage controller devices for high availability and increased throughput. This requires additional vendor software, which is known as multi-path drivers. Typically, different multi-path drivers from different vendors do not co-exist on a single node. Most multi-path packages install filter drivers that intercept Disk I/O and redirect to a particular HBA for fault tolerance and performance.
- Other Vendor-Supplied Filter Drivers
- In some cases, vendors supply additional filter drivers that load into the storage stack. These filter drivers may cause issues if they are loaded in the stack for other storage controllers.
- Storage Management Infrastructure
- There is currently no standard infrastructure for managing SANs. Different vendors have different management tools for configuring storage units and switches. A SAN that contains components from different vendors may not be manageable by using a single tool set. Carefully consider the manageability of a multi-vendor solution, and weigh the benefits of multiple vendors' components versus cost of ownership and ease of management.
- Storage Vendor Support
- Microsoft cannot provide end-to-end support for the complete solution without cooperation from the storage vendors. Microsoft supports a multi-vendor solution only if all the storage vendors also support the combination of components. Contact all the storage vendors before you deploy such configurations to make sure that you have an understanding of complete end-to-end support. If any vendor in the solution does not accept that this is a supported configuration, Microsoft does not support the complete solution.
- Storage Virtualization
- New technologies are becoming available that provide a layer of storage virtualization across multiple storage controller devices. These technologies are supported in a configuration only if they are part of the complete solution on the Cluster HCL. It is important that any storage virtualization software or hardware is part of the qualified cluster solution on the HCL.
- Maintaining a Qualified Configuration
- Over time, new versions of drivers and firmware will become available, and vendors will require upgrades for the configuration to remain supported. Consider the fact that different vendors qualify their configurations at different times, and, therefore, it is always possible that a new driver or HBA firmware will be required from one vendor when it is not yet supported by another vendor. Making sure that upgrades are performed in a controlled and seamless way across the storage fabric is a complex management task.
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