Great blog about the consequences of upgrading to vSphere 6 and new enhanced functionality.
Recently I have seen a number of internal emails here at EMC asking about our recommendations around All Paths Dead (APD) and Permanent Device Loss (PDL) in vSphere 6 on our storage arrays – mostly VPLEX to be specific. There have been significant changes in APD/PDL in vSphere 6 which is why the questions are being posed. It just so happened that I was updating my VMAX TechBook on this topic but as I won’t publish until June I thought I could preview it here.
Let’s start with a quick primer here on the terms.
All paths down or APD, occurs on an ESXi host when a storage device is removed in an uncontrolled manner from the host (or the device fails), and the VMkernel core storage stack does not know how long the loss of device access will last. VMware, however, assumes the condition is temporary. A typical way…
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