vCAP-DCA

Hi All
Long time since my last update mainly down to studying for the vCAP-DCA exam. I am afraid the news from the exam is not good. I arrived at my test centre in London and went over all the normal stuff. I sat down and then started the exam.

For obvious reasons I have to watch what i put on here.

The exam started and i set to work. as detailed by many others the exam is a Live Lab, but the problem I had was with the connection to the LAB. It was soo slow and unresponsive and made the exam very tiresome and frustrating. I got about 3/4 into the exam and then ran out of time. I suspect that will result in me having to retake the exam and i am defo not paying for the retake at £300.

I found no questions difficult and if I was unsure VMware do give you all the documentation for all the product sets you are looking at, so I tried to look up a few items that I was unsure about, but due to the problems with the slow LAB I couldn't read the documentation.

I have complained about the LAB and it seems I am not the only one taking it outside the USA who has had this problem.

Going back to the preparation for the exam I found the following sites very helpful in assisting me with preparing for the exam

vFAIL.NET - Brilliant site and the summary of each section is good- However I would always try and look more in depth at each section. Do a quick Google or look for the VMware paper.

KendrickColeman - Is one better then the above and provides a download section containing all the PDFs and web2PDF's that you will need to help you master the section.

Over all I would like to thank both the above, but also have to stress you have to know how to use the more advanced features in a day to day install. Just reading here on how to use the Powershell cmdlets or the vMA is not enough as you will be asked questions that will prove if you know how to use the features.

I am going to chase VMware to see whats happening with my complaint. fingers crossed it is positive.

ESXI Managment / VCAP

Hi All
I have been looking at the management of ESXi over the last few weeks. It would appear there is very little out there on managment of it for advacned administrators such as myself. Most people seem to be content with managing it from vCenter or the console. I have found several times it is not easy to do this and when troubleshooting it dosnt provide much information or assistance.

VMware do have a vMA. This is a basic Linux machine running as a mock service console. It allows you to attache multiple ESX and ESXi machines to it and then manage then using more or less the same commands as you would from the service console in a full ESX install. There are limitations as it is not a service console and is only a collection of scripts that run to mock a service console.

I will be focusing on creating a powershell based management pack for my company in the next couple of weeks. I will not be able to release that on here but I should be able to release a cut down version. I am not sure if I am going to do it in an appliance or as a standalone package. lets see how board I get.

I am also now looking to complete the VMware Certified Advanced Professional exam that has just been released. Will try and relay some helpful study information if I can.

Host currently has no management network redundancy.

Hi All
After a nice holiday I cam back into the office and eased myself back into the flow. I had a small rebuild to conduct from vSphere ESX to vSPhere ESXi U2. Rebuilding the hosts was very simple but after found I was being given this message on the vCenter

Host currently has no management network redundancy.

I could not see any problems as the vmKernal port had 4 vmnics. I reconfigured the HA for each host and then the problem started again.

In the end I looked around and found the following KB from VMware

KB1004700

Details that you can disable this alarm and it is a small glitch in the vCenter .

Disk now becoming the limiting factor

Hi

I was conducting a health check today at a site using some very well spected hardware. The site was using dual chase IBM x Servers. These are an amazing bit of kit with a second chase attached which is filled with CPU and RAM. Over all each host had 32 cores and 128GB of RAM. I was onsite conducting a second health check after all the recommendations I had provided from the first health check has been implemented. Everything with the site is looking good until i started conducting a performance analysis of the disk, CPU and MEM. All the hosts are sitting around 40-60% CPU and 10-20% or RAM so we are talking around 23500MHz of CPU and 20 GB of RAM. But when looking at the disk performance of the FC I was seeing some serious delays in storage command processing. The hosts had been built and had been paired with 4 single port 4GB FC cards...... The customer had only connected two and was only pushing traffic down a single HBA. This was causing some serious problems with hi IO VMs such as SQL and exchange.

This is not the first customer I have seen this and it would not appear that the limiting factor in the majority of enterprise size VMware environments is disk IO. I know there are now 8GB FC systems available (i have worked with a Compellent 8GB installation) but It would now appear that storage IO needs to be the first resource investigated when looking into performance problems. This is where I will be looking from now on.

VMware Dropping ESX...... and vSphere 4.1

After the press release of VMware ESX vSPhere 4.1 on Tuesday, i have been reading a few things about it. The biggest change from what I can see is that VMware have said this will be the last version of ESX, after 4.1 ESX will be the only version VMware will make.

This will result in more people using Powershell and the the vMA to manage there virtual machines. I personally have been using both of these management methods for sometime and so the switch isn't going to be a massive headache for me but I can imagine most people having problems switching over.

The other item i noticed is that the vCenter only appears to have been released in a 64Bit version. This from what I can understand is the resolve the very annoying problem with TOMCAT using loads of memory on the majority of 32Bit versions. I have never seen this on the 64bit installs I have done which leads me to believe VMware just want everyone to use the working 64bit version.

I have not had a chance to download the trial and play around but I think I will give the ESXI version a go once I have some time to play with it in the lab.

Thanks

VM Balloning

Hi Again
I have recently been having a large number of calls from clients regarding slow responding VM's. Upon investigating the VMs I have often found that they are ballooning and the MEMCTL driver is showing as active in ESXTOP.

After looking over the ESX/ESXI server there appears to be plenty of free memory, VMware tools is up to date and Virtual hardware is level 7.

I then looked at the VMs settings from the "Edit settings" of the VM in vCenter. I Then went to the resources tab and could see there were a problem.....

For some reason there were limits on the memory for less than the memory granted at the configuration of the VM. I asked why these were set and the customers all say they have not set these settings. Once the limits are moved the VM ballooning stops and the machines start to respond ok.

It was then clear that the majority of all VMs had these limits on them, some causing problems and some just set to the memory of the VM. On a vCenter with 500+ VMs it is very time consuming to remove all of these. I had a quick Google to see if there was a Powershell script to do it, why make one if someone else has already, found a very helpful script that someone had already created. I checked the script over and then ran it in the vSPhere Power CLI

"

Connect-VIServer
$ResourceAllocationInfo = New-Object VMware.Vim.ResourceAllocationInfo
$ResourceAllocationInfo.Limit = -1

# Get the Managed object for each VM
Foreach ($VM in get-vm | get-view) {
# Create a fresh VirtualMachineConfigSpec
$VirtualMachineConfigSpec = New-object VMware.Vim.VirtualMachineConfigSpec
$i = 0
# If the CPU Allocation is not unlimited add CPU to our spec.
IF ($VM.ResourceConfig.CpuAllocation.Limit -ne -1) {
$VirtualMachineConfigSpec.cpuAllocation = $ResourceAllocationIn
$i++
}
# If the Memory Allocation is not unlimited add Memory to our spec.
IF ($VM.ResourceConfig.MemoryAllocation.Limit -ne -1) {
$VirtualMachineConfigSpec.memoryAllocation = $ResourceAllocationInfo
$i++
}
# If $I is gt 0 then we have a VM to fix... Trigger the reconfig task.
IF ($I -gt 0) {
write-verbose "Removing limits on $($VM.Name)"
[void]$VM.ReconfigVM_Task($VirtualMachineConfigSpec)
}
}

"

I take no responsibility for this script so please be careful. You will see all the tasks in vCenter for when the settings are being set to unlimited.


Thanks

W2K8 VM using all free memory but not doing anything.

Hi All
Not updated in a while mainly due to the fact my company has had me doing help desk work to cover sickness. Will never understand why they just don't just get another consultant but that's another story for another time.

My first real work for a while has led me to a massive infrastructure of 45 hosts and 600 VMs, not the biggest environment but not the smallest either, I was onsite doing a check for some upgrade work and a minor health check. One of the internal guys was looking over a VM that was using all the allocated memory but wasn't doing much. I had a look and it was a Windows Server 2008 machine on a 64Bit installation acting as a file server. Now I remember reading an article about this and racked my brains for a few mins before I remembered that I made a note of it.....

http://support.microsoft.com/kb/976618

This is the problem. Windows Server 2008 uses all the free memory to cache files that it thinks are going to be accessed. This saves time and speeds up the file server role. But as my customer found out, it was causing apps that run on the file server to run slow and unresponsive. The above fix was applied to alter the memory behavior, after the reboot I monitored the VM for the rest of the week. Memory was higher then I would expect but there was plenty free for the apps to run. Would appear the above article works.

My customer however did hesitate in applying the fix as it does detail that it is resolved in Windows 7 and Windows sever 2008 R2, but it would appear it has not been addressed in the 64Bit versions of the operating systems.

flat-vmdk files

Hi All
Had an interesting problem that I thought I would share. A customer today had deleted all the files associated with their VM except the flat-vmdk file. The resulted in the machine still running but was not being able to power the machine down or edit it in anyway.

They powered down the VM and attempted to recreate the VM and attach the flat=vmdk as a disk, but this is not possible. The flat-vmdk file contains the RAW data of the vmdk and is often not seen when using the datastore browser. What is used to connect disks is a vmdk file that is a metadata file and contains information mapping to the flat-vmdk. So without this you cannot connect any disks.

I have done a few of these on VI3 but this was my first vSphere and I wanted to check that nothing had changed in VM Hardware 7. So I found this article from VMware.

Gave it a quick going over and it all looks the same.

So I created a new VM with exactly the same disk layout, same size disks and everything. I created in on the same datastore as the original VM was located.

After this I powered on the VM, this is just to create the flat-vmdk file for the VM.

I then powered down the VM

logged onto the command line of the ESX sever and typed the following command to take me to
the VMFS locatation. cd/vmfs/volumes/datastorename/new_vm

From here I could remove the new VMs Flat-vmdk type ls to make sure you can see the file and then type rm new_vm-flat.vmdk You will be prompted to confirm

Once this has been removed you can then move the original flat-vmdk from the broken VM type cd ..
cd old_vm

You can then type the following to move the file. mv old_vm-flat.vmdk /vmfs/volumes/datastorename/new_vm
This will then move the flat-vmdk to the new VM working directory. You now need to browse to the new directory cd .. and then cd new_vm type ls to make sure the file is located in the directory.

now we need to change the name of the flat-vmdk to match the file in the vmdk header. we need to do a cat on the file to show us what it is looking for. type cat new_vm.vmdk you will see something like this.

-------------------------------------
# Disk DescriptorFile
version=1
CID=fb183c20
parentCID=ffffffff
createType="vmfs"

# Extent description
RW 8388608 VMFS "vmdisk0-flat.vmdk"

# The Disk Data Base
#DDB

ddb.virtualHWVersion = "4"
ddb.geometry.cylinders = "522"
ddb.geometry.heads = "255"
ddb.geometry.sectors = "63"
ddb.adapterType = "lsilogic"
ddb.thinProvisioned = "1"
-------------------------------------
We need to make a note of the line RW because we are going to change the name of our flat-vmdk to match this.

Once this has been noted type the following to change the name of the old flat-vmdk. mv old_vm-flat.vmdk new_vm-flat.vmdk This will then rename the file to that of the flat-vmdk listed in the file we ran cat against. you can check this by typing ls.

If there the same the VM will power on.

The customer I completed this for was very happy is going to delete file more carefully in future.

Welcome - About me

Hi Everyone
Well this is my first blog, I thought I would start by saying "Hi" and telling you all a little about myself.

I am 23 and work as a Virtualization consultant. I work for a large Cloud based virtualization company. We specialize in many things as well as cloud computing. We have a Professional Services and a Managed Services team and I am the main managed services consultant, taking the lead on all services provided.

I have 4 years experiance in Virtualization and focus mainly on server Virtualization using VMware. I am a VCP 3 and VCP 4 as well as Microsoft 2003 MCSA security and one exam away from my MCTIP Enterprise administrator for 2K8 Server. I worked mainly in finance and telecommunications company's providing 3rd line support prior to vendor escalation. My consultancy role takes me all over the UK and I carry out all levels or work from installing a full vSphere or Hyper-V system from scratch to performing health checks of installations on VMware and other virtualization technology's.

I have decided to start a blog for the reason that most technical people do. I find keeping track of everything I learn difficult and often when people ask me questions I am too busy or have to dig out notes. Doing things this way I can share all my info and just refer people to my blog.

Well I have loads to share and will post everything up as soon as I can.

Thanks all