Yellow Bricks

by Duncan Epping

What happens if all hosts in a vSphere HA cluster are isolated?

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I received this question through twitter today from Markus who was going through the vSphere 6.7 Clustering Deep Dive. And it is fairly straightforward: what happens when all hosts are isolated in a cluster, will the isolation response be triggered?

https://twitter.com/RealRockaut/status/1029652167735631874

I wrote about this a long long time ago, but it doesn’t hurt to re-iterate this. Before triggering the isolation response HA will actually verify the state of the rest of the cluster. Does anyone own the datastore on which the VMs that are impacted by this isolation run? If the answer is no, the ownership of a datastore is dropped during the election, then HA will not trigger the isolation response. I will try to update the book when I have time to include that, hopefully, that means a new version of the ebook will be pushed out to all owners automatically.

Must read white paper: Persistent Memory performance with vSphere 6.7

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Today I noticed this whitepaper titled: Persistent Memory Performance on vSphere 6.7. An intriguing topic for sure as it is something “relatively new and something I haven’t encountered too much in the field. Yes, I talk about Persistent Memory, aka NVDIMMs, in my talks usually but then it typically relates to vSAN. I have not seen too many publications from VMware on this topic, so I figured I would share this publication with you:

The paper starts with a brief intro and then explains the different modes in which PMEM can be used, either as a “disk” (vPMEMDisk) or surfaced up to the guest OS as an NVDIMM (vPMEM). With the latter option, there’s also the ability to have some form of application awareness, which is referred to as the 3rd mode (vPMEM-aware).

I am not going to copy and paste the findings, as the paper has a lot of interesting data and you should go through it. One thing I found most interesting is the huge decrease in latency. Anyway, read the paper and get familiar with persistent memory / NVDIMMs, as this technology will start changing the way we design HCI platforms in the future and cater for low latency / high throughput applications in traditional environments.

What happened to MaxCostPerEsx41DS? It doesn’t seem to work in vSphere 6.x?

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Today I received a question which also caught me by surprise, someone updated from vSphere 5.0 and he noticed that when doing an SDRS Maintenance Mode that the setting MaxCostPerEsx41DS did not work. This setting actually limits the number of active SvMotions on a single datastore. You can imagine that this can be desired when you are “limited” in terms of performance. I was a bit surprised as I had not heard that these settings changed at all. Also, a quick search on internal pages and externally did not deliver any results. After a discussion with some support folks and some more digging, I found a reference to a naming change. Not surprising I guess, but as per vSphere 6.0 the setting is called MaxCostPerEsx6xDS. So if you would like to limit the number of SvMotion’s active at the same time, please note the change in names.

For more background on this topic I would like to refer to Frank’s excellent blog on this topic here.

You asked for it: vSphere 6.7 Clustering Deep Dive ebook, now available!

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We knew when we released the paper version of the book that many would yell: What about an e-book? Although sales numbers of the Host Deep Dive and previous Clustering Deep Dive books have shown that by far most people prefer a printed copy, we decided to go ahead and create an ebook as well. It is not as simple unfortunately as simply uploading a PDF or an MS Word file. We had to spend evenings reformatting the book in an e-book authoring tool, compile it, review it, fix issues, compile again etc. Nevertheless, it is done!

So what we did is we just uploaded it to Amazon, and we made it available for 14,95 USD, or whatever that roughly converts to in your local currency in your local store. We also noticed there was a bundling option, so as soon as the ebook and the paper copy are linked you can buy the ebook alongside the paper copy for only 2,99 USD. (Linking the book may still take a couple of days, we’ve initiated the process with Amazon and are waiting for them to complete it.)

You wanted it, so go out and pick it up, right before the weekend! Also, note that we have both the ebook and the paper version available right now, we are working on linking the books, so you can get a nice deal for both versions. Also, I would highly recommend picking up the Host Deep Dive books as well, and while you are at it pick up the VDI guide, it is an excellent read! Amazon links are on the right side for your convenience.

My top VMworld session picks

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Every year I post a list of my favorite VMworld sessions, my top picks. There are way too many sessions to see, but these are definitely the sessions I would like to attend personally. That could be because of the speaker, or the content, and preferably both. Yes I know, this list will have some great sessions missing, not because I did not like the abstract or speaker, but simply because I forced myself to limit this list to 10. Before we get started, here are the two sessions I have scheduled, make sure to sign up for those while you still can, as both seem to be at 80+ % capacity right now

  1. The Power of Storage Policy-Based Management [HCI1270BU] – Cormac Hogan & Duncan Epping
    Tuesday, Aug 28, 12:30 p.m. – 1:30 p.m.
    The world of software-defined storage moves at a rapid pace, and VMware is one of the biggest enablers. In this session, Cormac and Duncan will guide you through the world of software-defined storage initiatives at VMware and provide a primer to VMware vSAN, VMware Virtual Volumes (VVol), persistent cloud-native storage options (Project Hatchway), the VMware vSphere APIs for I/O filtering, and the binding factor in these cases: storage policy-based management. Be warned: We will bring demos!
  2. vSphere Clustering Deep Dive, Part 1: vSphere HA and DRS [VIN1249BU] – Frank Denneman & Duncan Epping
    Monday, Aug 27, 12:30 p.m. – 1:30 p.m.
    In this session, Duncan and Frank will take you through the trenches of VMware vSphere Distributed Resource Scheduler (DRS) and vSphere High Availability (HA). Find out about options to optimize your DRS settings for your specific requirements and goals, such as if you should be load balancing on active or consumed memory, as well as what has recently changed in the DRS algorithm and if it will impact DRS behavior. And for vSphere HA, you will learn about when it restarts virtual machines (VMs), what kind of restart times to expect, and where you can find evidence that a VM (or multiple) have been restarted. You will find out about all of these items and more. Prepare to dive deep, as the basics will not be covered.

Here are my top picks, note that although I picked Ravi’s session from the Extreme Performance Series, all of them are worth attending!

  1. Extreme Performance Series: vCenter Performance Deep Dive [VIN1759BU] Ravi Soundararajan
    Tuesday, Aug 28, 5:00 p.m. – 6:00 p.m.
    In this talk, you will get a brief description of the internals of VMware vCenter before going into basic performance troubleshooting and monitoring techniques. Find out about various tools for analyzing resource usage, important metrics like sessions and API calls, and database performance (primarily for the vCenter Server Appliance, but also for vCenter Server for Windows). You will get to understand the differences between vCenter and Platform Services Controller, and consider the impact of linked mode and plug-ins/extensions. By the end of the talk, you’ll understand how your vCenter works, when you may need multiple vCenters, and how Platform Services Controller factors into performance. xPerfSeries
  2. Tech Preview: The Road to a Declarative Compute Control Plane [VIN2256BU] Maarten Wiggers & Frank Denneman
    Tuesday, Aug 28, 12:30 p.m. – 1:30 p.m.
    Declarative control planes are becoming increasingly popular in the industry. Instead of explicitly defining configurations, declarative control planes tell the architecture what the desired state should be. The desired state could be high priority, or keep particular VMs or containers separate. Within the software-defined data center (SDDC), VMware vSphere offers two declarative control planes: one for networking and one for storage. However, there is no declarative control plane for compute yet.
    Compute policy provides a framework to allow our customers the flexibility and control of VM placement and resourcing decisions based on the user’s encompassing application needs. In this session, you will learn about the capabilities introduced in the VMware Cloud SDDC as a path to achieve that goal.
  3. Clustering Deep Dive 2: Quality Control with DRS and Network I/O Control [VIN1735BU] Niels Hagoort & Sahan Gamage
    Tuesday, Aug 28, 2:00 p.m. – 3:00 p.m.
    In this session, you will go through the trenches of network-aware VMware vSphere DRS and vSphere Network I/O Control. You may ask yourself what these two have to do with each other as, unfortunately, not many people know about the enhancements added to the DRS algorithm around network-aware load balancing. If you want to understand how this can help prevent problems from occurring with network-intensive workloads like NFV, then this is a session you cannot miss!
  4. Project Fractal – The Easy Button for Edge Computing [IOT2593BU] – Dennis Lu & Sridevi Ravuri
    Tuesday, Aug 28, 4:00 p.m. – 5:00 p.m.
    Come and learn about how VMware can accelerate your adoption of Edge Computing by dealing with the additional complexity and cost of infrastructure management at the Edge, helping you quickly achieve the cost savings and revenue growth benefits of Edge Computing. This is also a great opportunity to shape the direction of VMware’s edge services to help fit customer needs.
  5. vSAN Deployment Topology and Availability Deep Dive: What You Need to Know [HCI2040BU] Paudie O’Riordan & Mansi Shah
    Wednesday, Aug 29, 8:00 a.m. – 9:00 a.m.
    Today, VMware vSAN can be deployed in many different form factors; for example, vSAN 2-Node ROBO, vSAN Fault domains, Stretch Cluster with and without local protection, and more. These deployment models make vSAN quite flexible and unique. This session will help you understand the different trade-offs and focus on the benefits and overheads of the choice you’ve made in your vSAN proposed design. Join Mansi and Paudie as they discuss these topologies in depth from both an engineering perspective and a practical real-world implementation. Paudie and Mansi will take a no-nonsense review of how to approach designing a fault-tolerant vSAN deployment and give real-world examples of how to achieve the best design from both an availability and performance perspective.
  6. Top 10 Automation Requests and How You Can Save Time [VIN2527BU] Alan Renouf & William Lam
    Monday, Aug 27, 2:00 p.m. – 3:00 p.m.
    After working firstly as customers and secondly at VMware, Alan and William have encountered hundreds of ways to save time through automation. In this session, they will take you through the top automation requests and how they were completed, teaching you not only how to reproduce them yourself, but also giving you a framework to enable you to automate your top 10 requests.
    This session will include a number of techniques and languages, such as PowerShell, PowerCLI, Python, Java, .NET, and simple web applications with JavaScript.
  7. Data Lifecycle Management in Hybrid Clouds [HCI1705BU] Christos Karamanolis & Ilya Languev
    Tuesday, Aug 28, 2:00 p.m. – 3:00 p.m.
    The focus of IT and DevOps organizations is shifting from storage toward data management independent of infrastructure and locations. This trend is partly driven by a new generation of applications that extract business value from data (big data, analytics, machine learning). Customers need cost-effective data storage but also data mobility, copy management, and on-demand access as business requirements and IT investments evolve. Join Christos Karamanolis (CTO, Storage and Availability) and Ilya Languev (Principal Engineer) as they outline the VMware vision around data lifecycle management that spans private data centers and public clouds. They will discuss VMware’s R&D investments in this space and use real-world examples and demos to highlight the benefits for our customers, both for traditional and cloud-native applications.
  8. VMware CTO Panel: What’s Over the Horizon? [CTO3496PU] Ray O’Farrell, Christos Karamanolis, Chris Wolf, Shawn Bass, Pere Monclus
    Tuesday, Aug 28, 5:30 p.m. – 6:30 p.m.
    VMware CTOs spend significant time assessing emerging technology trends, taking a practical look at their potential impacts and opportunities for VMware. This session explores emerging areas, inclusive of edge, the Internet of things, artificial intelligence (AI)/machine learning (ML), SD-WAN and network service mesh, distributed data management, and more. There will also be ample time for you to have your most pressing questions answered.
  9. Smart Placement of Workloads in Tomorrow’s Distributed Cloud [CTO2161BU] Daniel Beveridge
    Tuesday, Aug 28, 1:00 p.m. – 2:00 p.m.
    This session will offer a look at the evolution of cloud as we move from a nega-cloud-focused experience into a more distributed cloud experience where compute evolves toward a mesh of resources. Find out about a technology project sponsored by VMware’s Office of the CTO that has developed a novel approach to the placement of workloads in a vast marketplace of providers, resulting in a seamless cloud burst experience across a range of providers. You will learn about some cutting-edge cloud technology that points toward a new way of consuming cloud services with an emphasis on reducing cost, improving user experience, and offering increased flexibility and agility in workload management.
  10. Optimizing vSAN for Performance [HCI1246BU] Cormac Hogan & Paudie O’Riordan
    Tuesday, Aug 28, 3:30 p.m. – 4:30 p.m.
    The VMware vSAN team gets many questions on performance. For example, does adding a second disk group improve performance? Does adding a stripe width to an object make things faster? Does increasing the MTU size matter? Does mixing SAS and SATA make a difference? Join this session for answers to these sorts of questions. Paudie and Cormac will discuss the results of various performance tests they initiated in their labs to reach these conclusions. You will learn about the benchmark tool of choice, HCIBench, as well as all the different nuances that can make a difference to your benchmarking results.

Also note, there’s a long list of “deep dive” session at vmworld this year, do a search and register before it is too late!