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Cormac Hogan

About Cormac Hogan

Cormac Hogan is a Senior Staff Engineer in the Office of the CTO in the Storage and Availability Business Unit (SABU) at VMware. He has been with VMware since April 2005 and has previously held roles in VMware’s Technical Marketing and Technical Support organizations. He has written a number of storage related white papers and have given numerous presentations on storage best practices and vSphere storage features. He is also the co-author of the “Essential Virtual SAN” book published by VMware Press.

Virtual SAN – Sizing Considerations

UPDATE: Now that Virtual SAN is out of beta and generally available, there is updated guidance around sizing.  The information written below was written during the beta, and has now been superceded by the new guidance.  Please read this blog post for the latest recommendations or directly download the GA edition of the Virtual SAN Design and Sizing Guide.

A common question that I have seen recently around Virtual SAN (VSAN) is how limits on number of components, disks, etc., translate into capacity and policy limits. I will attempt to cover some of the basics in this post. However for a deeper explanation on the various sizing and design considerations, please check out the updated Design & Sizing Guide which you can find in the VSAN beta community documents section in the POC Kit folder. If you are not yet signed up for the VSAN beta, why not? Click here to register. The beta community has a wealth of information, including documentation, hardware guidance and some great discussions with our R&D engineers. A great place to start if you just want to read up on Virtual SAN, or indeed, kick its proverbial tires.

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Virtual SAN Beta Refresh Updates

There is a new beta release of Virtual SAN (VSAN) available today for those of you participating in the beta. You can download the new bits of the beta refresh by clicking here (you will need a valid MyVMware login to access it). This post covers a number of areas around the beta refresh. It will cover how to upgrade to the new release, a fix for the AHCI controller issue that we encountered in the beta testing, the new PowerCLI fling, changes to certain VSAN limits and the winners of some of our VSAN contest and surveys. Read on to learn more about the changes in the VSAN beta refresh.

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Virtual SAN – Maintenance Mode Monitoring

Over the past couple of days, I’ve been looking at the behavior of Virtual SAN (VSAN) from the context of placing a host into maintenance mode. With VSAN enabled on the cluster, the administrator is given a number of options to choose from:

  • Ensure accessibility
  • Full data migration
  • No data migration

The thing with VSAN is that although a virtual machine’s compute may not be on the host that is being placed into maintenance mode, there is still a strong possibility that part of the virtual machines storage object may be on the local disks of that host, especially if you are using a NumberOfFailuresToTolerate policy setting (which you should be). So if ‘Ensure accessibility’ or ‘Full data migration’ is chosen, components of the virtual machines storage objects may have to be migrated from the host entering maintenance mode.

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What’s new in vSphere 5.5 – the video!

Hi all,

Now that VMworld 2013 is over (both America & Europe), I noticed that a bunch of the break out sessions are now up on YouTube. Kyle Gleed (@VMwareESXi) and I delivered a 1 hour presentation on “what’s new in vSphere 5.5”, including ESXi, vCenter and Storage. You can watch the whole thing here.

If you didn’t get to VMworld, we hope you like this. If you did get to VMworld, but would like a refresh on all the new vSphere 5.5 features, you might like to watch this again. Of course, the best bit starts at about 26 minutes in, but don’t tell Kyle that :-)

 Get notification of these blogs postings and more VMware Storage information by following me on Twitter: @VMwareStorage

Virtual SAN & Disk Groups

[Updated for VSAN beta refresh – November 2013] I had a number of questions and queries on VSAN over the past week at VMworld 2013 in Europe. Many of these questions related to the role of disk groups. I will try to answer a number of them in this post.

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Virtual SAN & support for Horizon View Desktops

We had an interesting announcement here at VMworld EMEA yesterday, where the audience was told that Horizon View version 5.3 will support and have interoperability with Virtual SAN (VSAN). This was a timely announcement as our performance engineering team just released some very impressive VDI numbers using VMware’s new Virtual SAN storage system and View Planner.

In a nutshell, a 3 node VSAN cluster could host in the region of 90-100 desktops per host. More importantly the team observed linear performance scalability as more nodes were added to the cluster, with the team testing a 7 node VSAN cluster and successfully hosting around 650 desktops using the VDI Planner benchmarking tool.

Link to the benchmark results.

The VSAN beta is well underway. If you would like to get access to the material available on the VSAN beta communities site, including POC kit, sizing guide, and other collateral, register for the VSAN beta via vsanbeta.com.

Get notification of these blogs postings and more VMware Storage information by following me on Twitter: @VMwareStorage

New Virtual SAN (VSAN) white paper available

A new Virtual SAN (VSAN) white paper is now available. VSAN is a new storage solution from VMware that is fully integrated with vSphere. The paper looks at all aspects of the new VSAN architecture, including what the requirements are, the converged storage and compute aspects, the hybrid nature of using SSD & HDD, and the new storage policies, bringing to reality VMware’s vision for software defined storage. Also the considerations that must be taken into account when deploying VSAN are covered as well as interoperability with other vSphere products is also discussed.

You can download the white paper from the VMware Technical Resources site here.

Link to the What’s New Virtual SAN white paper.

Get notification of these blogs postings and more VMware Storage information by following me on Twitter: @VMwareStorage

VSAN and Storage Controllers

UPDATE: Now that Virtual SAN is officially released, the hardware compatibility list has been updated.  This list has changed considerably since the Beta of VSAN, and some devices are no longer supported.  For the latest and most up-to-date information, please check the VMware Compatibility Guide for Virtual SAN.

There have been numerous questions around supported storage controllers with regards to VSAN. Those of you who have been following the various posts and watching the presentations/webinars on VSAN will have seen the requirement that pass-through mode must be supported if you wish to use a RAID Controller. The purpose of this article is to delve deeper into this requirements and explain why VMware are making that recommendation for storage controllers.

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A list of VSAN references – from VMware bloggers

A lot of folks have been looking for VSAN reference materials now that vSphere 5.5 is available and the VSAN beta can commence in earnest. Many VMware employees, who are also bloggers, have put together quite a bit of information to get you well and truly on your way to a successful VSAN deployment. This post will pull this information into one place of reference.

First of all, to get us started, here are a few useful links on how to sign up to the VSAN beta, the link to the beta community and some demos, videos and labs:

Now let’s list some VSAN information from VMware’s own bloggers.

Of course, a quick search of the vSphere blog will also show a few VSAN or Virtual SAN posts (some by our R&D folks), and more of which will be added over the coming months.

I hope you find this single point of reference for VSAN links useful.

Get notification of these blogs postings and more VMware Storage information by following me on Twitter: @VMwareStorage

Virtual SAN (VSAN) videos now available

A selection of VSAN videos are now available on the VMwareTV YouTube Channel. These videos cover basic install, VM Storage Policy creation and modifying, as well as how VSAN handles various failure conditions (including interop with vSphere HA). Check them out here:

Get notification of these blogs postings and more VMware Storage information by following me on Twitter: @VMwareStorage