NVMe-oF – Cody Hosterman

July 12, 2023September 26, 2023

NVMe-oF Features and Fixes in Pure Storage’s vSphere Plugin Versions

It can be difficult to understand the work that has gone into Pure Storage’s vSphere plugin if you’re not digesting the release notes for every release. Because NVMe-oF is going to become more and more relevant I think it’s worth highlighting some recent improvements we’ve made around NVMe-oF in the vSphere plugin. I’ll mostly be referencing the vSphere plugin release notes in this blog. I strongly recommend installing the vSphere plugin for all of your vCenter + FlashArray needs but it is a requirement of following along with the new features of the plugin later.

The first update that involves NVMe-oF datastores was back in April of 2020 and was version 4.3.0. We added support for identification of NVMe-oF datastores. A good first step!

July 19, 2022October 25, 2023

Migrating From SCSI To NVMe on vCenter (Part 1 – Live Migration)

This is going to be broken up into two parts- first, a live migration where no VMs get powered off during the migration; second, a migration where you temporarily power off VMs attached to the SCSI datastore.

Why would you want to do it one way or another?

Pros of live migration:

No VM downtime
Simpler configuration changes and overlap. Less to go wrong or mess up

Pros of powering off VMs:

The total migration time will be significantly less because no data will have to be moved. Currently VMware doesn’t support XCOPY (even on the same array) for NVMe-oF

January 21, 2021January 22, 2021

ESXi NVMe-oF Namespace IDs, LUNs, and other Identifiers

In the world of SCSI, a storage device is generally addressed by two things:

LUN–Logical Unit Number. This is a number used to address the device down a specific path to a specific array, for a specific host. So it is not a unique number really, it is not guaranteed to be unique to an array, to a host, or a volume. So for every path to a volume there could be a different LUN number. Think of it like a street address. 100 Maple St. There are many “100 Maple Streets”. So it requires the city, the state/province/etc, the country to really be meaningful. And a street name can change. So can other things. So it can usually get you want you want, but it isn’t guaranteed.
Serial number. This is a globally unique identifier of the volume. This means it is entirely unique for that volume and it cannot be change. It is the same for everyone and everything who uses that volume. To continue our metaphor, look at it like the GPS coordinates of the house instead of the address. It will get you where you need, always.

So how does this change with NVMe? Well these things still exist, but how they interact is…different.

Now, first, let me remind that generally these concepts are vendor neutral, but how things are generated, reported, and even sometimes named vary. So I write this for Pure Storage, so keep that in mind.