Hosting the Desktop: VMware View or Citrix XenDesktop?
Posted on 08.Mar 2010 by Ray Heffer in Citrix, VDI, VMware, Virtualisation
Since VMware View was released in November 2009 and Citrix XenDesktop 4 in the same month, you could be mistaken that this is a game of tennis at Wimbledon with all the hype about each product. I first started working with desktop virtualisation in a VDI sense (not terminal server based) when VMware VDM 2.0 beta was released in 2007 (now VMware View), and for a moment VMware seemed to be ahead of the game. Prior to that, I had to put up with Citrix Desktop Broker which was made end-of-life a short while after its release. Then Citrix released XenDesktop 2.0, and with desktop provisioning making storage issues a thing of the past thanks to Citrix Provisioning Server (formerly an Ardence product), the ball seemed to be firmly back in Citrix’s court.
VMware ESX Error: Unable to connect to the MKS: vmx connection handshake failed for mks of…
Posted on 03.Mar 2010 by Ray Heffer in VMware, VirtualisationWhen you power on a virtual machine with VMware ESX VI3 or vSphere it may reach 95% progress in the tasks, but when you open the console you’ll notice the error: “Unable to connect to the MKS: vmx connection handshake failed for mks of /vmfs/volumes…”.
Finally received my VMware vSphere VCP certificate in the post today!
Posted on 20.Feb 2010 by Ray Heffer in Business & IT, VMware, Virtualisation
I passed my VCP4 back in December, and after many months of waiting I finally received my VCP certificate on vSphere 4 today!
I’m also working on some study material for those of you that are aiming for a VMware VCP certificate. If you subscribe to my RSS feed, you won’t miss out when it’s published!
VMware vSphere Virtual Machine Live Clones Across Datacenters
Posted on 17.Feb 2010 by Ray Heffer in VMware, Virtualisation
Prior to VMware ESX 4 (vSphere) it was not possible to clone a running virtual machine to another datacenter, or to a virtual machine data store that wasn’t available on the source host. Now with VMware vSphere it is possible to clone a running virtual machine to another datacenter, even if the destination data store is not presented to the source host.
How To Fix Host Not Responding Error with VMware ESX, vSphere in vCenter
Posted on 05.Feb 2010 by Ray Heffer in VMware, Virtualisation
Virtualcenter looses connectivity to an ESX or vSphere host, and all of the virtual machines that are running on the host show as ‘disconnected’. You will also see that the host has ‘not responding’ in brackets next to it’s name.
This one is very simple to fix, as it is usually caused by the host agent service (mgmt-vmware) failing due to a dead process.
Running Rings Around Virtualisation
Posted on 01.Feb 2010 by Ray Heffer in VMware, Virtualisation
In 1987 when I was just 11 years old, I used my first real PC, other than the Sinclair Spectrum and Commodore 64 (1984) of course… an Intel 80386 Personal Computer with a green screen CRT display. Bundled with it was a book called ‘80386 Programmer’s Reference Manual‘. Back then I was fascinated with computer programming and machine code, and although little of the book was understood at the time, much of it is still relevant today. The book was published in 1986, and one of the sections covered processor privilege levels.
Privilege levels determine what rights the procedure being executed has when issuing instructions, or accessing I/O ports and memory addresses. There are 4 privilege levels for x86 processor architecture, and these are called rings. The four rings (0 to 3) are designed to protect the hardware resources, keeping user applications at level 3 (the least privilege) and the operating system kernel at ring 0 (the most privileged).
Installing VMware tools on a Linux guest
Posted on 19.Jan 2010 by Ray Heffer in Linux, Scripts & Commands, VMware, VirtualisationStart the VMware Tools installation
Using the VMware VI Client, right click on the Linux guest and select Install/Upgrade VMware Tools.
Mounting the CD-ROM
You’ll need to mount the CD-ROM on the Linux guest.
# mount /dev/cdrom /mnt
VMware ESX 3.x Snapshots
Posted on 12.Oct 2009 by Ray Heffer in VMware, VirtualisationSnapshots are a fantastic way of providing a quick and reliable method of rolling back the state of a virtual machine, should something go astray following an patch or update. VMware VCB also uses virtual machine snapshots to quiesce the VM prior to taking the backup data.
However, in larger environments where there may be tens or hundreds of VMware ESX servers, snapshots can also be a pain in the backside if there is no control over who is using them. Why? Because snapshots work by creating a delta VMDK that records the changes in blocks, a process called copy-on-write (COW). Over time the delta VMDK file will grow, and depending on the level of I/O within the VM it could grow faster on some virtual machines and not others.
The danger only presents itself if the datastore where the VMDK resides reaches it’s capacity. When this happens, virtual machines that are not thin-provisioned should continue to run with no problems, but think about these situations:
1) You have other virtual machines in the same datastore using snapshots.
2) You have one or more virtual machines on thin-provisioned disks.
3) You have powered off virtual machines, that need to be powered on.
In all of the above scenarios if the datastore is full then the affected virtual machines will be suspended (paused). Virtual machines with thick-provisioned disks will continue to operate as the VMDK already has the full allocated of storage space available. Virtual machines that are powered off, and need to be powered back on will fail as they won’t have enough disk space to create the virtual swap file.
