Unix and Windows, to zone or not to zone
We have a Brocade SAN switch connected to EMC storage and multiple Unix servers. We are planning to connect a Windows cluster to it and we would like to implement zoning in the Brocade switch.
We would like to know the best way to implement the zoning. Does zoning help improve performance in any way? Do we have to zone each independent servers or one common zone for Unix and one for Windows?
It's always best to zone out Unix and Windows into different zones. Since the EMC FA ports are usually defined per operating system type you can define specific storage ports into zones containing the different operating systems. Keeping Windows away from Unix removes the possibility of Windows servers attempting to write signatures on Unix volumes.
Although a common zone will usually be OK for management separation of specific OS types, using the smallest zones possible will isolate error traffic to the specific zones and keep your SAN humming along even when one HBA goes berserk. The only affected servers would be the servers within the same zone as the flaky HBA.
For your cluster, each server in the cluster needs to have access to the same disks. A SCSI reserve command needs to be communicated to the quorum resource for control of the cluster so every server in the cluster needs access to it. The same holds true for data volumes in the cluster. I would create a zone that has all the server and storage ports allocated to the cluster in the same zone.
By the way, NEVER associate any other resources to the quorum disk in your cluster. Cluster failover happens much faster and cleaner when the quorum resource is separate from application resource disks. You also need to make sure that each server in the cluster sees each disk as the same drive letter, and same "physical disk" resource in the registry. This makes resource failover clean and fast.
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This was first published in June 2003