ESXi 6.0 November 2015 CBT Fix Patch (Build 3247720)

VMware has published a patch for ESXi 6.0 that resolves the (new) CBT Bug documented in KB2136854.

Product: VMware ESXi 6.0
Release date: November 25, 2015
Patch: ESXi600-201511001
Build: 3247720
Links: KB2137545 | Download

This patch updates the esx-base VIB to resolve an issue that occurs when you run virtual machine backups which utilize Changed Block Tracking (CBT) in ESXi 6.0, the CBT API call QueryDiskChangedAreas() might return incorrect changed sectors that results in inconsistent incremental virtual machine backups. The issue occurs as the CBT fails to track changed blocks on the VMs having I/O during snapshot consolidation.

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How to create custom vCenter Alarms from Events

In my last article I’ve created a custom vCenter alert with a special event trigger. I’ve received a question about how to figure out the trigger event string to be used for creating alarms.

The vSphere Client shows the following error event:vcenter-event

To create an alarm based on this event, you have to create a new alarm and use the following event trigger:

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Why you should protect your Virtual SAN Network

As a common best practice you should separate management, vMotion and Virtual SAN traffic from production traffic. This is not only a performance requirement, but also for security concerns. Compared to management traffic which is encrypted and requires authentication and vMotion traffic which is impracticable to eavesdrop, Virtual SAN traffic presents a large surface area to attacks.

This article explains why it is critical to keep Virtual SAN traffic in protected networks and what can happen when you ignore this guideline. I am also explaining how you can detect and monitor such attacks.

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Building a Single-Node VSAN

single-node-vsanI was wondering if it possible to speed up my Intel NUC based ESXi with Virtual SAN. The idea is that compared against vSphere Flash Read Cache, Virtual SAN can use the SSD not only as read cache but also as write buffer. This post explains how you can create a Virtual SAN Datastore on a single ESXi host from the command-line without a vCenter Server.

It goes without saying that this is neither the idea behind Virtual SAN nor officially supported by VMware. It also violates VMware’s EULA if you are running Virtual SAN without a VSAN license. To assign a licence you need a vCenter Server and wrap the single ESXi into a Cluster.

My configuration for this test:

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How long are Virtual Machines stunned for Snapshots and vMotion?

I’ve read this excellent article by Cormac Hogan explaining why and when a Virtual Machine receives a “stun”. This post is a follow-up explaining how you can determine the duration of a Virtual Machine stun on the most common vSphere functions:

  • Create a Snapshot
  • Delete a Snapshot
  • vMotion

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5th Gen Intel NUC with 32GB Memory

Intel NUCs with ESXi are being used as home servers and in many home labs. If you are generally interested in running ESXi on Intel NUCs, read this post first. Officially, it is limited to 16GB memory which might come a little bit short for virtualization labs. Recently Crucial has launched 16GB DDR3L modules for an affordable price (Intelligent Memory was the first in the market with 16GB modules, but they were quite expensive). I’ve ordered two Crucial 16GB modules (CT204864BF160B) and tested them in my 5th Gen Intel NUC (NUC5i5MYHE).


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What’s Inside an ESXi vm-support Bundle?

When you open a Support Request (SR) at VMware, the Global Support Services usually requests you to collect diagnostic information. You can create this log bundle with a special command line tool (vm-support), with the vSphere (Web-)Client or with the API. No matter how you create the bundle the result is always the same: a .tgz file containing your ESXi Host name and the creation date with a size of about 30 – 300MB.

This post explains what’s inside this log bundle, but instead of simply extracting the file and looking at the result, I am going to take a look on how the file is created and what’s part of the process.

Why is it important to know? Because it does not only contain data that allows VMware GSS to identify your issue, but also to help yourself to enhance your troubleshooting skills. The script gathers the output of many useful commands and there is nearly no black magic involved. You do not need special tools or internal VMware knowledge to make use of this log bundle.


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USB 3.0 devices detected as USB 2 in ESXi 6.0 and 5.5

In my latest post USB Devices as VMFS Datastore in vSphere ESXi 6.0 I had a problem with USB 3.0 devices that are detected as USB 2 in ESXi. I know that USB 3.0, also known as eXtensible Host Controller Interface (xHCI), is supported in ESXi 6.0 and ESXi 5.5 Build 2143827 or later. Unfortunately all of my devices are detected as USB 2.1, despite the USB 3 hub was visible. This problem applies to both, USB devices in path-through mode, and USB devices mounted from the command line with usbarbitrator disabled. The solution was quite simple and not related to an ESXi, but to a UEFI configuration.

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Pre-installed ESXi 6.0 on SD Cards or Flash Drives

Many ESXi installations are running on SD Cards or flash drives. In my opinion, it’s a good practice. The hypervisor itself requires about 150MB, and the full installation on a SD Card is less than 1GB, without diagnostic partitions. VMware recommends using a 4GB or larger USB/SD device. When you want to install ESXi and you don’t use auto-deploy, install servers or other automation tools you typically have to mount an ESXi ISO file to your server management system (iLO, iDRAC,…) or work with a physical installation media. This is somewhat slow and uncomfortable, but there is a little trick to make the installation faster.

You can prepare the USB/SD device with the ESXi installer, plug it into your server and install it to the device itself by overwriting the installer. You can also use customized installers when your hardware requires special drivers. Read more »

USB Devices as VMFS Datastore in vSphere ESXi 6.0

In the last years I’ve seen many requests in forums and blogs where people are trying to use USB devices like USB sticks or external hard disks as VMFS formatted datastore. It was actually possible in vSphere 5, but very picky. Some USB flash drives were working, others not. In vSphere 6, this behavior has been changed obviously. This post explains how you can use USB devices as datastore on your ESXi host. Of course, this is neither a supported, nor a performant storage solution, so use at your own risk. Read more »