William Lam

Required ESXi advanced setting to support 16+ node VSAN Cluster

03.13.2014 by William Lam // Leave a Comment

This evening I came across a very interesting VSAN knowledge base article KB 2073930 which states: to support a VSAN Cluster with greater than 16+ nodes, an ESXi Advanced Setting must be configured. The wording in the current KB is a bit confusing as it mentions the advanced setting must be applied to all hosts and then it mentions it should only be applied to the "additional" hosts. I have reached out to engineering and confirmed that the setting should be applied to ALL ESXi hosts and the KB will be corrected shortly. After applying this setting, you will also need to reboot your ESXi host for the changes to take affect.

The advanced setting we are interested in is called CMMDS.goto11 and you can check its current value by running the following ESXCLI command:

esxcli system settings advanced list -o /CMMDS/goto11

The following ESXCLI command will configure the required setting (default it is 0):

esxcli system settings advanced set -o /CMMDS/goto11 -i 1

The reason this setting is disabled by default is that it does consume a tiny amount of memory, we are talking about sub ~150MB per ESXi host. Though this amount is extremely small, the VSAN Engineers wanted to be very cognizant of smaller VSAN deployments and not have to require additional resources if it is not necessary. In my opinion if you plan to eventually scale beyond 16+ nodes in a VSAN Cluster and you can afford the additional memory overhead, then I would recommend enabling this setting as part of your default configuration so you do not need to do it later. If not, you can always do it later, but you know how that goes 🙂

To assist with this change, I have created two scripts: vSphere SDK for Perl and PowerCLI which will automate the configuration of this advanced setting for ALL ESXi hosts within a VSAN Cluster.

Disclaimer: These scripts are provided for informational and educational purposes only. It should be thoroughly tested before attempting to use in a production environment.

You can download the sample vSphere SDK for Perl script called: enable16PlusVSANNodeSupport.pl

Here is an example of how you would run it:

./enable16PlusVSANNodeSupport.pl --server vcenter55-1.primp-industries.com --username root --cluster VSAN-Cluster

UPDATE (07/27/17) - Here is a PowerCLI script called VSANLargeClusterAdvSettings.ps1 which contains two functions (Get-VsanLargeClusterAdvancedSetting and Set-VsanLargeClusterAdvancedSetting) for retrieving and updating the necessary ESXi Advanced Settings to enable large vSAN Clusters for ESXi hosts running on 5.5, 6.0 & 6.5. There are two different KBs depending on the version of ESXi, please see https://kb.vmware.com/kb/2073930 and https://kb.vmware.com/kb/2110081 for more details.

Finally, some fun VSAN trivial from the engineering team. You may have noticed the advanced settings is called "goto11" which I was initially scratching my head over on why the engineers would name it that. I initially though it was either binary 11 OR it was a literal GoTo statement. It turns out, the answer can be found in this YouTube video here. Thanks to Dinesh Nambisan for sharing this awesome little tidbit. I wonder what other surprises lies in the code 🙂

Automating Horizon View deployments using VCT & cURL

03.11.2014 by William Lam // 1 Comment

Last week I spent a couple of days playing around with the new Horizon View Configuration Tool (VCT) Fling and as part of my "exploration" of VCT, I needed to re-run the deployment. Going through the guided wizard the first time was fine, but if you needed to do that 5-10 times, then it was not very fun. Since VCT was a simple web application, I decided to fire up one of my favorite tool, Firebug to do some poking around.

It turns out the payload request was actually very simple and it contains all the variables for each of the parameters that a user would specify through the UI and a single HTTP POST request is then sent to the web application for deployment. I took all the variables and created a simple shell script that a user can easily edit without having to worry about fat-fingering on the UI as there is no form validation at the moment and then send the POST request using my other favorite tool cURL.

Disclaimer: These scripts are provided for informational and educational purposes only. It should be thoroughly tested before attempting to use in a production environment.

You can download the script here called automateVCT.sh

Before running the script, you will need to edit the variables for your environment and if you have an existing Active Directory server, then there are some variables that you can leave off. Towards the bottom of the script, there is an infinite loop that will run to continuously to check the current status which is then printed on the screen every 10 seconds. For practical use, you will probably want to change the timing to something a bit longer like every 5 minutes for a status.

Here is an example of executing the script:

As you can see from the screenshot, once the request has been accepted by VCT, the status will be printed on the screen which is the same status shown in the UI. If everything was successful, you should eventually see the status display the IP Address of your Horizon View environment like the following:

This script really came in handy for testing VCT and I thought it would be great to share it with the community so you can automate the deployment of your Horizon View environment using VCT!

Useful Links - Installing Mac OS X in a VM & P2V'ing Mac OS X

03.10.2014 by William Lam // 1 Comment

A couple of weeks back I received an interesting email regarding a couple of topics related to Apple Mac OS X and vSphere. The first one was related to the steps required for installing Mac OS X in a Virtual Machine. Though the process for installing Mac OS X in a Virtual Machine is pretty straight forward, there is an additional step that you must preform before you can get started. This was actually something I ran into when I first tried to install Mac OS X in a Virtual Machine. I found this handy online resource by VMware called Guest Operating System Installation Guide that provides the exact steps required and you will find a link for each of the supported Mac OS X systems as shown in the list below.

Mac OS X 10.9 (Mavericks)
Mac OS X 10.8 (Mountain Lion)
Mac OS X 10.7 (Lion)
Mac OS X Server 10.6 (Snow Leopard)
Mac OS X Server 10.5 (Leopard)

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