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Evaluate PernixData FVP with replayed Production IO Traces

Using synthetic workloads to test drive PernixData FVP might result into odd findings. The most meaningful approach to test FVP is to deploy the software to production in monitor mode, let Architect do its magic and enable acceleration after checking the recommendations after a couple of days. Despite it is possible to deploy FVP, test drive, and remove it, without any downtime to virtual machines, this approach might not fit to all environments.

pernixdata-fvp-replay-workload

If you have separate DEV/QA environments with sophisticated load generators, the solution is obviously. If you don't have that, there is another option by record production I/O traces and replay them in a FVP accelerated test platform.

Read More »Evaluate PernixData FVP with replayed Production IO Traces

Howto NOT Benchmark PernixData FVP

Whenever I evaluate a new storage hardware or technology, I do some basic performance testing with VMware I/O Analyzer. I/O Analyzer is virtual appliance (Fling) provided by VMware that runs Iometer to generate synthetic I/O workloads. After installing PernixData FVP my first idea was to compare the raw performance of my storage, against the performance with PernixData FVP. However, I quickly noticed that synthetic workloads do not create any useful results. The upside is that I've learned much about how their caching operates so I'm publishing my results anyway. Actually, it's not a problem with PernixData FVP itself, it's just how host based caching works.pernixdata-fvp-vmware-io-analyzer

Conclusion: Don't use synthetic workloads to test caching solutions! PernixData FVP works as expected but synthetic I/O workloads are no meaningful benchmarks for host based caching. I am going to test with realworld applications in another article to show how they can take advantage of FVP.

Read More »Howto NOT Benchmark PernixData FVP

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: com.vmware.vc.vsan.RogueHostFoundEvent
alarm-trigger-RogueHostFoundEvent

Read More »How to create custom vCenter Alarms from Events

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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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 »Pre-installed ESXi 6.0 on SD Cards or Flash Drives

How to hide a Virtual Machine

This post explains how you can hide a VMware based Virtual Machine from designated users or the entire vCenter Server infrastructure. I'am explaining different scenarios where you can hide Virtual Machines including:

  • Hide Virtual Machines from Groups or Users in vCenter
  • Hide Virtual Machines from the entire vCenter Server
  • Hide Virtual Machines from root on Single ESXi instances
  • Find hidden Virtual Machines

To clarify, this post does not cover techniques to cloak that the Guest OS is running on a virtual machine, instead of bare metal.

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How to get "Use Windows session" Checkbox to work in VCSA6

You've just installed vSphere 6 vCenter Server Appliance (VCSA) and want to use the "Use Windows session authentication/credentials" checkbox like you know it from the vCenter Server running on a Windows Server?

You've already added an Active Directory as Identity source, and you can login with AD users, but the "Use Windows session authentication/credentials" still does not work?

You see the following error messages in the vSphere Client:
Windows session credentials cannot be used to log into this server.
windows-session-credentials-cannot-be-used

Or in the vSphere Web Client (If the checkbox is greyed out, install the Client Integration Plugin from the bottom of the login page):
Incorrect username/password
vsphere-web-client-incorrect-password

This post explains how to get the "Use Windows session" checkbox to work

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How to identify that Linux is running as a Virtual Machine?

tuxFor troubleshooting or in scripts you might want to identify if you Linux is running as a Virtual Machine. If you work with puppet you might be familiar with facter which provides the facts "is_virtual" (true or false) and "virtual" (Virtualization type).

There is another handy tool called virt-what that is available in Fedora (13+), Red Hat Enterprise Linux (5.7+ and 6.1+), Debian, Ubuntu, ArchLinux and Gentoo, and it can be compiled from source on just about any Linux.

Read More »How to identify that Linux is running as a Virtual Machine?