Cormac Hogan

Cormac Hogan is a Director and Chief Technologist in the Office of the CTO in the Hyper Converged (HCI) Business Unit 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.

Recent Posts

Announcing the All New vSAN Networking Guide

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I’m delighted to announce a brand new vSAN Networking Guide. This is now published on our storagehub site. This new updated guide covers everything from support statements, the basics of NIC teaming on the vSAN network, including what options are available and the pros and cons of each approach, as well as supported topologies for Read more...

Announcing vSphere 6.5 Core Storage white paper

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I’m delighted to announce the availability of a new vSphere 6.5 core storage white paper. The paper covers new features such as VMFS-6 enhancements, policy driven Storage I/O Control, policy driven VM Encryption, NFS and iSCSI improvements and of course new limit increases in vSphere 6.5. There are too many VMware folks to thank for Read more...

Scaling 2-node VSAN (ROBO) to a 3-node or more

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We recently had a question from our field staff on behalf of a customer who is considering a 2-node VSAN (remote office/branch office) deployment. The query was regarding scale out of the VSAN deployment, should they reach resource limits on the 2-node implementation. We gave this some consideration, and the following were the sequence of Read more...

Considerations on Virtual SAN Maintenance Mode and Disk Operations

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With the recent launch announcement for Virtual SAN 6.2, we have been revisiting some of our previous guidance and best practices around Virtual SAN operations. Possibly the most important of these is disk device handling and replacement procedures. This has historically been tied to host maintenance mode for reasons that I shall explain shortly. Those Read more...

A new vRealize Log Insight Content Pack for Virtual SAN

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Attention Virtual SAN (VSAN) users. A new Log Insight content pack has just been released specifically for Virtual SAN. For those of you not familiar with Log Insight, this product does automated log management through log analytics, aggregation and search. It allows administrators to analyze terabytes of logs, perform smart parsing to discover structure in Read more...

An important KB for VSAN Stretched Cluster

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Today we released a very important KB article, KB 2135952, for VSAN stretched cluster. It informs customers on how to handle a split partition/network partition scenario on a VSAN stretched cluster. The reason we released the KB was as follows: In the event of a split-brain scenario in a VSAN stretched cluster, where the two Read more...

VSAN Design & Sizing – Memory Overhead Considerations

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This week I was in Berlin for our annual Tech Summit in EMEA. This is an event for our field folks in EMEA. I presented a number of VSAN sessions, including a design and sizing session. As part of that session, the topic of VSAN memory consumption was raised. In the past, we’ve only ever Read more...

Help us with the future direction of SIOC

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Storage I/O Control (SIOC for short) has always been one of my favorite core storage features in vSphere. It was introduced way back in version 4.1, and has been instrumental in helping us address the pesky “noisy neighbor” virtual machine problem. These are virtual machines that from time to time generate a huge amount of Read more...