When it comes to designing storage for virtualization, there is one important step that happens in every environment, it seems. It is the whiteboard step where each ESX(i) server is drawn up to have two or more HBAs to two or more different switches to a storage controller with two or more interfaces. This also occurs with iSCSI with multiple initiator interfaces going to different switches to the storage controller. This is shown in Figure A below, and can be tweaked and changed in many ways with different storage products or network configurations:
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But the catch here is that each host has its own path configuration. And while the datastore properties on one host may be correct, there is no guarantee that the next host in the cluster is configured as you expect it to be. The properties of the datastore can show which path is active and change the multipathing policy, but this is a configuration that is live for each host in a cluster.
The vSphere Client makes it easy to take a quick look at a host's configuration for paths to a datastore. What tricks have you used to check to ensure that each host has the requisite and planned number of paths to datastores? Share your comments below.
Rick Vanover is a software strategy specialist for Veeam Software, based in Columbus, Ohio. Rick has years of IT experience and focuses on virtualization, Windows-based server administration, and system hardware.