Dell offers a Multipathing Extension Module (MEM) for vSphere, and in this post I´ll highlight how to “manually” install it on a ESXi 5.1 host. I will not cover the network setup part of the equation, but rather go through the simple steps required to get the MEM installed on the hosts in question.
First of all, you need to download the MEM installation package. At the time of writing, the latest version is v18.104.22.1682203, available from equallogic.com. One the archive file is aquired, unzip it and upload the dell-eql-mem-esx5-22.214.171.1242203.zip file to a shared location available in your environment. For the example below, I have used a VMFS datastore that is available to all the hosts in this particular cluster.
--> Please see the rest on the blog : http://vninja.net/virtualization/installing-dell-equallogic-multipathing-extension-module-mem-vsphere-5-1/