Virtualization VMWare

Cold migration in VMWare – What is it?

So the topic of what is a cold migration (in VMWare vmotion speak) came up in a conference call today with a customer.

It is a migration strategy when there are CPU compatibility constraints  between certain revisions of CPUs, it basically means there is no path to use v-motion as such so will associated outages.
When does it occur?

As mentioned, cold migration is a strategy or a decision to migrate virtual machines between different revisions of CPU (whether it be manufacturer or models). An example might be going from an AMD chipset to an Intel chip.  There are cases that going from a same vendor CPU requires an outage so cold migration would be an option.  More information on what to check, how to check can be found here

What happens? 

Quite simply, the virtual machine is powered off on the source host and powered on, so there is an outage but as long as both ESXi servers have visibility to the same shared storage, then cold migration can be very fast and the virtual machine downtime kept to a minimum.
The difference to vMotion

Biggest difference, vMotion is (typically) performed without any downtime on the virtual machine where as cold migration requires an outage to power down and power up the virtual machine on the destination host.

Another notable difference it happens at a management network layer and not the VMKernel layer (which vMotion uses)

That is cold migration in a nutshell!

Virtualization VMWare

VCP 510 exam – My thoughts

Having recently sat the VCP 5 exam, I thought I would offer some tips and study advice.  Overall, there are 85 multi-choice questions and you have 90 mins to complete and their is a lot more focus on new features, troubleshooting, and configuring than previous versions of the exam which was usually based around limitations and maximums.

 

 

Networking

  • VMKernel securing – how (and where) to do it.
  • Load balancing policies
  • Path Selection policies – Quite a few questions on these.
  • Traffic shaping
  • VDS – Lots on this topic. What features are unique to VDS and what aren’t,
  • Promiscuous mode vs forged transmits – About 2 questions involving these
  • Restarting management network – how to do it in vSphere 5
  • Securing your host – turning off ssh etc.
  • Uplinks – what are they and what do they do. Relationship with vSwitches
  • CNA – Question around image profiles and driver certification
  • ISCSI and implications of changing certain parameters such as CHAP

Storage

  • New features: VMFS3 vs VMFS 5, migration to VMFS5 – what changes and what doesn’t. Maximum file size supported
  • VSA – How to configure. Valid states of a VSA
  • RDM – Physical compatibility vs Virtual
  • Storage Profiles – Learn what it does.
  • VMKernel interation with storage array, what the array does and what the kernel does
  • VAAI – Benefits of VAAI and what the supported array can do.
  • Trouble shooting storage performance – What counters to look at

Advanced Features

  • HA – What it does.
  • FT – Why you would use it – use cases
  • DRS – Ports for DRS and HA
  • vMotion/EVC – Where to configure and requirements around CPU. NPIV and vMotion compatibility
  • Resource Pools, shares, limits and reservations – Lots of questions around these, learn what increasing and decreasing each element does and the effect.
  • Performance tuning and troubleshooting – They give you line graphs and ask you to understand and diagnose the issue, scenario based troubleshooting. (I.e Image shows error, what is the cause), ESXtop
  • Memory conservation – TPS vs ballooning
  • Upgrading from ESX3 to ESXi5 – One question on this, basically you can’t do it.
  • Upgrading from ESX4 to ESXi5 – rules, methods and things you need to look out for.
  • How to back up a ESXi host before upgrading
  • Understanding alarm warnings and alerts and how to configure
  • vApps and IP allocations, and what objects they contain.
  • Log file configuration. Increasing etc
  • vCenter Server – What extra capabilities does it give you over managing a host directly.
  • Auto Deploy – Learn Image profiles and how to use.
  • VSA – Quite a few on this, how to upgrade from earlier version was one question
  • Modifying Users and permissions and the impacts

Hope that helps.

Virtualization VMWare

Thin vs Thick: VMFS formats.

This took me a little while to get my head around the concepts.

But here is my understanding:

Thin In this particular format, the of the VMDK file on the datastore is equal to the amount that is used within the VM itself as it zeros out the space prior to I/O being written, so for example if you create a 200GB virtual disk, and you populate it with 100GB worth of data, the VMDK will be 100GB in size and will grow as more data is added to it.

Thick The VMDK file on the datastore is the size of the virtual disk file that you provisioned but no prezeroing takes place like it does in thin format.  So for example if you create a 200GB virtual disk and write 100GB worth of data to it, the VMDK will still appear as 200GB in size but only contain 100GB worth of data.

Eagerzeroedthick The “truely” thick virtual disk, the size of the VMDK file within the datastore is equal to the virtual disk size that is provisioned. If you create a 200GB virtual disk, and write 100GB worth of data the VMDK will be 200GB and contain 100GB worth of data and 100GB of zero’s. Which format is the best? There are pro’s and cons for each. Thin format requires more monitoring and cant be used with RDM’s where Thick/Eagerzerothick are not as efficient as thin and one might not see as much space savings when implementing this type.

Virtualization VMWare

Enabling SSH and SFTP on ESXi 5.x Host

So I had just built a ESXi 5 VM when I wanted to upload some ISO’s into a datastore, alas SSH is turned off by default in ESXI 5

So, first part is to turn it on, you need to be physically at your ESXi box in order to do this part.

At the ESXi console screen

Logon using the root account

Select “Troubleshooting Options” from the menu

In the next menu, select “Enable SSH”, you will notice that it says ‘Disabled’ in the right hand pane

Press enter to change to enable

Thats it!, you can now quit out of there and go onto the next part which is to get the SFTP server running, truth is it is missing by default in ESXi 4

So lets get it

ssh into your esxi box using the root account.

cd /sbin */ Changes to the right directory
wget http://thebsdbox.co.uk/wp-content/uploads/2010/08/sftp-server.tar.gz */ Downloads sftp-server files
tar xzvf sftp-server.tar.gz */ Extracts file into current directory /sbin
rm sftp-server.tar.gz */ Removes file now that we have extracted it

Log out.. Thats it! You should now be able to SFTP files to and from your ESXi 5 host!

HP Virtualization VMWare

HP 3PAR recovery manager for vSphere.

What is it?

HP 3PAR Recovery Manager Software for VMware vSphere enables the protection and rapid recovery of virtual machines and VMware datastores

What does it look like?

<insert image here>

What can it do?

It provides virtual copy management and allows you to take LUN-level snapshots of virtual machines and datastores through the vSphere management GUI by using array-based snapshots that are quick, space efficient, and virtual machine aware.

The plugin makes it possible to create hundreds of virtual copies. The number of virtual copies to retain and the retention period for each virtual copy can easily be specified

This plug-in can do granular restores at the VMFS level, the virtual machine level, or the individual file level.

Neat stuff!

If you want to know more, get in touch and email me or visit http://www.hp.com/go/3PAR

 

 

HP Storage VMWare

HP 3PAR Dynamic Optimisation and VMWare vSphere

In a nutshell, HP 3PAR Dynamic Optimisation Software is a software license/product enabled on the storage array itself that can provide a non-disruptive way to make changes to storage volumes hosted on the HP 3PAR Storage System.

Storage administrators can move volumes between different drive types or tiers (SSD, Fibre Channel, SATA/Nearline), leveling volumes as new drives are added into the array, all without outages or impacting any hosts that the system is busy serving I/O to.

So how is this good for virtual environments? It can be used to move running VMs between different tiers without impacting what the virtual machines are doing.

Similarly, as new drives are added to the array, the LUN that ESX is using can be striped across the new drives on the fly without taking an outage at the ESX server level. VMWare’s vMotion technology offers somewhat similar functionality, but at the host layer.

Dynamic Optimization works at the storage layer, which can be used to optimize storage service levels while VMware vMotion can be used to optimize CPU utilization across multiple hosts.  Very similar to storage vMotion but all on the array itself!!

Pretty cool!

Personal Uncategorized

Blog hacked..

Thanks to a inadequate web hosting backup strategy, and a person with too much time on their hands.  cloud-land has been hacked through a vulnerability in the wordpress theme I was using. The result is many posts (along with associated files/screen dumps) have been lost.  I have managed to salvage some posts prior to this happening due to writing the actual content into a word document offline I kept before I published on here but still………Grumpy!!!

 

 

HP Virtualization VMWare

http://www.vmware.com/a/vmmark/ – Impressive Benchmarks by HP

Personally, I love seeing stuff and tests like these.

Whilst other technologist’s from representing companies may be quick to defend why their particular company’s hardware doesn’t get the top score they would of hoped. I try to take another angle on approaching these sort of benchmarks.

Why? I’ll break down the reasons why I think these are good to have.

Competitive – Simply, without some form of benchmark or competitor to design your products to compete with – Then technology wouldnt get as sophisticated as it has. Whilst server virtualization hasn’t been as prevalent or utilised as much as it is over the recent years. This particular benchmarking results show there are some worthy competitors to HP in the server market. It wouldn’t be as fun if it was a one horse race. This keeps the engineering team from Fujitsu, Dell, HP etc returning to the drawing board to make servers better and better.

And for a virtualization geek, this is exciting.

Trending – We can see how well servers do now and compare in five years time, There may be a gradual improvement in scores in the five years, or they may just increase exponentially.

Reviews – Simply put, some-one looking to buy a server for virtualization purposes has a great source of information on best performing models as a starting point to purchasing the right server. It also provides the consumer with an idea of just what elements affect server performance.

Well done to the top four server vendors – Fujitsu, Dell, HP and Cisco

Cloud

Cloud Computing – My own definition.

This will no doubt be tweaked over the years to come, but I thought I would share my own personal definition of what the concept of cloud computing is today.

“Cloud Computing refers to a virtual shared IT infrastructure where resources are provisioned as required from a shared pool of computer, storage and network on a pay per use basis via the Internet or WAN.”

Alternatively Wikipedia offers the following definition (Retrieved 5th August 2011 from (http://en.wikipedia.org/wiki/Cloud_computing)  “Cloud computing refers to the logical computational resources (data, software) accessible via a computer network (through WAN or Internet etc.), rather than from a local computer.”

My employer HP define it as “a delivery model for technology-enabled services that provides on-demand access to an elastic pool of shared computing assets.” from Finding the right cloud solutions for your organization,

Gartner defines cloud computing as a style of computing where scalable and elastic IT-related capabilities are provided as a service to customers using Internet technologies (Retrieved August 8th 2011 from http://www.gartner.com/technology/research/cloud-computing/).

So lets dissect these and dig out the common denominator between the three different definitions. The common theme or series of words are

“Shared, Instant, scalable and accessible”.

Behind all these definitions, you’ll see a lot of supporting detail that give a broader understanding of what the cloud really is.  I think the common themes really boil down to:

  • Instantly available – services that can be made immediately available
  • Scalability & elasticity – both are enablers of resources becoming instantly available. Without the cloud’s scalability, the whole speed aspect of the cloud goes away.
  • Shared resources – services that run within a set of shared resources – infrastructure or applications – that gain the benefit of multi-tenancy.
  • Accessibility – services that are processed over the Internet to the end user.

Private Cloud A private cloud refers to a cloud computing  environment which offers services within a single enterprise organisation and it’s firewall but may be hosted internally or externally to the organisation.

Public Cloud A public cloud refers to a cloud computing environment made available to the general public using the Internet and is external to the 0rganisation’s firewall that owns the environment

Hybrid Cloud A hybrid cloud refers to a computing environment that combines both private and public cloud computing environments.

Agree? Please comment and share your definitions, I’d love to read! There are more exciting posts to follow this one, particularly around Hybrid Cloud the many cloud offerings that HP have in this space. But for now, we’ll save it for another time

 

Virtualization VMWare

vSwitch vs Distributed vSwitch – What you need to know.

Content Lost due to hacking incident, they actually left the heading intact on this one – Will need to write this again 🙁

Personal

Schoolsnet – A blast from the past.

I was sitting in a catch-up session with the other two members of my local DCT cloud team today and one of them mentioned a piece of work he was involved in some years ago for local schools in the state of Victoria, Australia.

Having grown up in New Zealand (The land of the long white “cloud” :)), I recalled a BBS style network between primary and secondary schools in that each school was issued with a series of usernames and password that they could use to log on and chat to other use (schools/classes) all across New Zealand.  Interconnected networks or “internet”.

Now at the time, I thought this was amazing – please keep in mind that this is before the beast that we now know as the internet had taken off (think early nineties), and that was all run on analog systems including 14.4K modems and pretty ANSI terminal graphics.

It’s amazing how far modern technology, and the mediums in which we communicate with (blogs/twitter/facebook/email/smart phones/blah blah) have come. From text based systems to CMS, dynamic sites and social media – who knows what will be the next step.

Virtualization VMWare

Vsphere 5.0 and the new licensing scheme

OK so how license worked in vSphere 4 was straightforward: licenses were bought on a per CPU socket and you could run unlimited virtual machines (VMs) on the host until it crashed and burned (if you desired).

Things have changed in vSphere 5.0, whilst still working on a per socket basis, licenses also now come with a set amount of virtual RAM or vRam that can be allocated to VMs.

This could result in a customer to spend additional unnecessary dollars in additional licenses to be compliant with new vSphere 5 licensing scheme. If the customer buys hosts that can hold a large amount of RAM, these licenses costs can start to prove very costly.

To quote VMWare from their white paper on the matter.

"VMware vSphere 5 is licensed on a per-processor basis with a
vRAM entitlement. Each VMware vSphere 5 processor license
comes with an entitlement to a certain amount of vRAM capacity,
or memory configured to virtual machines. Unlike in vSphere 4.x
where core and physical RAM entitlements are tied to a server
and cannot be shared among multiple hosts, the vRAM entitlements
of vSphere 5 licenses are pooled, i.e. aggregated, across all vSphere
servers managed by a vCenter Server instance or multiple vCenter
Servers instances in Linked Mode"

 

More information on the licensing scheme can be found on VMWare’s website @ http://www.vmware.com/files/pdf/vsphere_pricing.pdf

HP Personal Uncategorized Virtualization

Welcome

My name is Andre Carpenter, I am a IT technologist from New Zealand working as a Consulting Solutions Architect at HP working in the Data Centre Transformation, Virtualisation and Cloud presales team based in Melbourne Australia. I also work with the APJ wider storage consulting practice just to spice things up.

My focus within the region of APJ/ANZ for the team is enterprise storage (3PAR), cloud offerings and virtualisation. I use the term “virtualisation” loosely as I rarely find myself dealing with the likes of Hyper-V and Xen, but more in the VMWare space and in particular server virtualisation.

I set up this blog to try and capture some of the interesting pieces of virtualisation and storage work as well as personal (and professional) interests and learnings I engage myself in on a day-to-day basis, for the most part these all revolve around Storage, Cloud computing and VMWare. The topics I write about will no doubt be written for myself to gain a better understanding or to share my experiences on topics I am confortable with – Sometimes I tend to choose subjects that I am not always very familiar with, write about them and share my findings, so hopefully you may gain something from them.

Although I work for HP, please understand that the views and expressions I share on this site may not necessarily reflect HP’s view of the IT world and that they are entirely my own.

You can find me on linkedin and twitter.

Thanks for visiting.

Andre

andre@cloud-land.com

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