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Cormac Hogan

About Cormac Hogan

Cormac Hogan is a senior technical marketing architect within the Cloud Infrastructure Product Marketing group at VMware. He is responsible for storage in general, with a focus on core VMware vSphere storage technologies and virtual storage, including the VMware vSphere® Storage Appliance. He has been in VMware since 2005 and in technical marketing since 2011.

VMware Storage Futures Video – Courtesy of VMUG Italia

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I mentioned last month that I would be presenting at the Italian VMUG event in Milan. Well, the VMUG guys recorded the session, so if you are interesting in seeing me talking about some of the cool storage projects we are working on internally here at VMware (such as Virtual SAN, Virtual Volumes & Virtual Flash), you can watch the video here:



The first few minutes are a little noisy, but that gets sorted out after a while. The one thing that is missing from the video is the disclaimer slide which I showed off at the beginning of the presentation. Its the usual stuff, in so far as we make no guarantee around the delivery of these projects. Hope you find it interesting, and much kudos to the folks at VMUG Italia for making this possible.

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

SIOC considerations with mixed HBA environments

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I’ve been involved in a few conversations recently related to device queue depth sizes. This all came about as we discovered that the default device queue depth for QLogic Host Bus Adapters was increased from 32 to 64 in vSphere 5.0. I must admit, this caught a few of us by surprised as we didn’t have this change documented anywhere. Anyway, various Knowledge Base articles have now been updated with this information. Immediately, folks wanted to know about the device queue depth for Emulex. Well, this hasn’t changed and continues to remain at 32 (although in reality it is 30 for I/O as two slots on the Emulex HBAs are reserved). But are there other concerns?

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New Storage Enhancements in vSphere 5.1U1

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vSphere 5.1 Update 1 is now available. For those of you running 5.1, there are a lot of critical fixes and enhancements, so I’d urge you to review the release notes and consider scheduling a slot to upgrade your infrastructure to this new release. There are updates for both vCenter and ESXi in this release.

Since this is the storage blog, I wanted to call out a few items which are directly relevant to storage and are addressed in 5.1U1, and these are features which I know a number of our customers have been waiting on.

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Virtual Machine I/O – Fairness versus Performance

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Many of you will have read various articles related to queue depths, especially in the area of LUN/device queue depths, and how these can be tuned to provide different performance for your I/O. However there are other queue settings internal to the VMkernel, which relate to how many I/Os a Virtual Machine can issue before it has to allow another virtual machine to send I/Os to the same LUN. What follows is some detail around these internal settings, and how they are used to achieve fairness and performance for virtual machine I/O.

Warning: These settings have already been pre-configured to allow virtual machines perform optimally. There should be no reason to change these unless guided to do so by VMware Support Staff. This is all about performance vs fairness. Failure to follow this advice can can give you some very fast virtual machines in your environment, but also some extremely slow ones.

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Italian VMUG – April 3rd, 2013 – Milan

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VMware User GroupThis is one for our Italian readers. If you are a VMware user and reside in Italy, we are having a great Italian VMUG event in Milan on April 3rd, next month.

I will be presenting on VMware’s Software Defined Storage vision, and giving some insight into some of the features VMware is currently working on which will make this SDS vision a reality.

Of course, there are some other notable speakers at the event too, such as Duncan Epping, Mike Laverick and Scott Lowe. This is a veritable who’s who of the virtualization world. It should be a super event, and I’d urge you to attend if you possibly can (and like all official VMUGs, it is free to attend). The full agenda is available here.

If you are interested, please sign up here as soon as possible. We would be delighted to see you there.

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

ESXi Slow Boot with MSCS

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This is an issue that has come up time and time again. The basic gist of the problem is that when there are Microsoft Cluster Service (MSCS) virtual machines deployed across ESXi hosts (commonly referred to as Cluster Across Boxes or CABs), the virtual machines are sharing access to disks which are typically Raw Device Mappings or RDMs. RDMs are LUNs presented directly to virtual machines. Because we are rebooting an ESXi host which one assumes now has the passive virtual machines/cluster nodes, the other ESXi host or hosts therefore have the active virtual machines/cluster nodes. Since the active nodes have SCSI reservations on the shared disks/RDMs, this slows up the boot process of the ESXi as it tries to interrogate each of these disks during storage discovery. So what can you do to alleviate it? Read on and find out.

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New NFS Best Practices Whitepaper available

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A new NFS best practices white paper is now available. The paper looks at all aspects of using NFS in a vSphere environment. The paper was created with the assistance of our partners from EMC (Isilon), HDS & NetApp, and tries to find common agreement as to what are the best practices. It discusses networking configuration options, interoperability with other vSphere components and advanced settings. You can download the white paper from the VMware Technical Resources site here.

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

VSA Licensing Explained

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There have been a number of queries recently in relation to licensing of the VSA with the 5.1 release. The VSA has a number of different licensing models depending on how it was obtained. In many cases, if you check your vSphere licenses via the vCenter License Administration view, you might observe that the VSA asset is reported as not licensed, in evaluation or expired.

So where do you check if you have a valid license for the VSA? Continue reading →

QLogic HBA Firmware Versions

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A question that I used to get quite regularly popped up again in the past week. It was basically a query about the version of firmware on QLogic 24xx & 25xx HBAs, and should customers flash/upgrade the firmware to newer/later versions?

The first thing to note is that the firmware for the QLogic HBAs is bundled with the driver package. The firmware and driver are both loaded when the ESXi host is booted. No separate firmware has to be installed on these HBAs. However, according to QLogic’s  KB article 1870, there might be occasion when you need to upgrade to a later driver package than that shipped with the ESXi. The point is that the newer driver package will once again bundle both the driver and the firmware, so again no need to consider upgrading firmware separately. I would always speak to one of our support representatives first however, before undertaking a driver upgrade.

Note that this is for the HBA only. For the Hardware iSCSI Adapter and the QLogic CNAs, the firmware is NOT embedded with the driver. Read the KB 1870 for more details. QLogic KB article 1849 has information regarding the latest drivers and firmware for VMware.

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

PEX 2013 Storage Picks

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As many of you are already aware, PEX, the VMware Partner Exchange for 2013 is almost upon us. As usual, I decided to call out a number of sessions which I thought you might be interested in attending from a storage perspective, if you are indeed attending PEX.

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