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2gbsparse Disk Format No Longer Working On ESXi 5.1

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I was recently made aware of an issue with my ghettoVCB script that after upgrading to ESXi 5.1, the ability to clone (or in this case backup) using the 2gbsparse disk format with vmkfstools was no longer working. The error that users were seeing was "The system cannot find the file specified." and I also confirmed this behavior by manually creating a VMDK and then trying to clone using the 2gbsparse format.

To give you some background, the 2gbsparse disk format is not a VMFS virtual disk format, it is part of the hosted desktop product (VMware Fusion, Workstation, Server & Player) disk format. This disk format was created to prevent cross-platform file system compatibility issue as pointed out in this VMware KB article. This issue does not exists on VMFS and hence this extra disk format is not necessary.

After some investigation, I found to use the 2gbsparse format in vmkfstools, you will need to load a specific VMkernel module called "multiextent". 2gbsparse was never officially supported on ESXi, you can not run a virtual machine with 2gbsparse disk format on ESXi and that is why a conversion maybe required when moving from a hosted product to ESXi. So by disabling unnecessary VMkernel modules that were not used made sense to help reduce amount of resources needed to load up. This is especially important with stateless deployments, where you want your ESXi host to load up as fast as possible.

Once you have enabled this VMkernel module, the 2gbsparse format will function again with vmkfstools. I also found that this was mentioned in the vSphere 5.1 release notes (yes, you should read the release notes)

To load the multiextent VMkernel module, run the following ESXCLI command:

esxcli system module load -m multiextent

To check whether the multiextent VMkernel module has loaded, run the following ESXCLI command:

esxcli system module list | grep multiextent

If you wish to persist this configuration after a system reboot, I found that you need to add the following command in a start-up script /etc/rc.local.d/local.sh as just setting the "enabled" flag is not sufficient for this particular VMkernel module.

localcli system module load -m multiextent

Note: We are using localcli because hostd may not be completely ready and you can either add a sleep/timer or just use localcli.

A Pretty Cool Method of Upgrading to ESXi 5.1

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I recently came across an interesting article by Andreas Peetz which shows you how to patch an ESXi host using an image profile that is directly available on VMware's online depot within the ESXi shell. I knew that VMware had online depots for use with VUM and Auto Deploy but I was not aware of this particular method, especially directly from the host.

Disclaimer: This method assumes you can install the default ESXi Image Profile with no additional drivers or packages, else you may have connectivity issue after the upgrade. If you still need to customize the ESXi Image Profile before installation, you will still need to use something like Image Builder and then upload that to your online depot.

Note: There are many ways that you can patch/upgrade your ESXi hosts, here is another article that provides more details for command-line only methods.

Before you get started, you will need to make sure that your ESXi host has the httpClient firewall rule enabled, else you will not be able to connect to VMware's online depot. To enable this, run the following ESXCLI command:

esxcli network firewall ruleset set -e true -r httpClient

Also make sure that your ESXi host can reach the following URL (you can specify a proxy if needed):

https://hostupdate.vmware.com/software/VUM/PRODUCTION/main/vmw-depot-index.xml

To view the available ESXi Image Profiles, run the following ESXCLI command (use the --proxy if you need to specify a proxy to reach VMware's online depot):

esxcli software sources profile list -d https://hostupdate.vmware.com/software/VUM/PRODUCTION/main/vmw-depot-index.xml

If you are able to successfully connect to the online depot, you see a list of all the ESXi Image Profiles that are available to you. You will see two ESXi 5.1 Image Profiles (these were recently published), one with VMware Tools and one without VMware Tools.

Note: Before you begin, make sure you do not have any running VMs and put your host into maintenance mode.

Let's go ahead and upgrade our ESXi 5.0 Update 1 host to latest ESXi 5.1. To install the new Image Profile, run the following command:

esxcli software profile update -d https://hostupdate.vmware.com/software/VUM/PRODUCTION/main/vmw-depot-index.xml -p ESXi-5.1.0-799733-standard

This can take a few minutes to complete depending on how fast you can pull down the Image Profile. Once it is done, you will see all the new VIBs that have been updated and you will be asked to reboot for the changes to go into effect and then you will be running ESXi 5.1! Pretty cool IMO!

Disabling IPv6 via Command-Line For ESXi 5.1 (Without Automatic Host Reboot)

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IPv6 for the VMkernel interface is now automatically enabled by default for the latest release of ESXi 5.1 and you may have also noticed the additional IP Address in DCUI after the host boots up.

IPv6 support has been around for awhile now and you can enable IPv6 by using the old vSphere C# Client or the new vSphere Web Client. If you enable or disable IPv6, you will need to perform a system reboot for the changes to go into effect. You also have the ability to enable/disable it via the DCUI, which also has been around for awhile as well.

UPDATE: 07/20/15 - For ESXi 6.0, the VMkernel module is name is now tcpip4 instead of tcpip3.

There is one very important thing to note if you do enable/disable IPv6 on the DCUI, after you made your changes and you wish to apply, there is a very important confirmation box that is displayed.

Carefully read the last sentence which is underline in red "In case IPv6 has been enabled or disabled this will restart your host". If you are not careful in reading the confirmation screen, you may hit yes and your host will issue a reboot. If you are going to use the DCUI to enable or disable IPv6, make sure you do not have any running VMs on your host and you should already have your host maintenance mode when making configuration changes to your host.

In addition to the two methods listed above (vSphere Web Client/C# CLient and DCUI) you can easily enable/disable IPv6 using ESXCLI (my preferred method) and restart the ESXi host when you get a chance.

To view whether IPv6 is currently enabled, run the following ESXCLI command (ESXi 5.5 Update 1 the VMkernel module is now called tcpip4):

esxcli system module parameters list -m tcpip3

As you can see from the screenshot above, ipv6 property is set to 1 which means it is enabled.

To disable IPv6, you just need to set the property to 0, run the following ESXCLI command:

esxcli system module parameters set -m tcpip3 -p ipv6=0

We can now reconfirm by re-running our list operation to ensure the changes were made successfully. All that is left is to perform a system reboot, you can either type in "reboot" or use the new ESXCLI 5.1 command:  

esxcli system shutdown reboot -d 60 -r "making IPv6 config changes"

Note: You can run the ESXCLI command locally on the ESXi Shell or you can run the same command remotely by specifying additional connection options & proxy through vCenter Server if you wish. Take a look here for additional connection options for ESXCLI.