Tag Archives: vcloud

My Journey to Double-VCDX

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It was back in 2011 when I started my journey to VCDX which was a fantastic learning experience which has helped improve my skills as an Enterprise Architect.

After achieving VCDX-DCV in May 2012, I have continued to put the skills and experience I gained during my VCDX journey into practice, and came to the realization, of how little I actually know, and how much more there is learn.

I was looking for another certification challenge however there was no additional VCDX certification tracks at the time. Then VCDX-Cloud and VCDX-Desktop were released, I figured I should attempt VCDX-Cloud since my VCDX-DCV submission was actually based on a vCloud design.

At the time I didn’t have my VCAPs for Cloud, so as per my VCAP-CID Exam Experience and VCAP-CIA Exam Experience posts explain, I formed a study group and sat and passed both exams over a period of a few months.

Next came the VCDX application phase, I prepared my design in a similar fashion to my original application which basically meant reviewing the VCDX-Cloud Blueprint and ensuring all sections have been covered.

I sad part about submitting a second VCDX is that there is no requirement to redefend in person. As a result I suspect the impression is that achieving a second VCDX is easier. While I think this is somewhat true as the defence is no walk in the park, the VCDX submission still must be of an expert standard.

I suspect for first time VCDX applicants, the candidate may be given the benefit of the doubt if the documentation is not clear, has mistakes or contradicts itself in some areas as these points can be clarified or tested by the panellists during the design defence.

In the case of subsequent applications,  I suspect that Double-X candidates may not get the benefit of the doubt, as these points cannot be clarified. As a result, It could be argued the quality of the documentation needs to be of a higher standard so that everything in the design is clear and does not require clarification.

My tips for Double-X Candidates:

In addition to the tips in my original VCDX Journey Post:

  1. Ensure your documentation is of a level which could be handed to a competent engineer and implemented with minimal or no assistance.
  2. Ensure you have covered all items in the blueprint to a standard which is higher than your previous successful VCDX submission
  3. Make your design decisions clear and concise and ensure you have cross referenced relevant sections back to detailed customer requirements.
  4. Treat your Double-VCDX submission equally if not more seriously than your first applications. Ensure you dot all your “I”s and cross your “T”s.

I was lucky enough to have existing Double-VCDX Magnus Andersson (@magander3) and Nutanix colleague review my submission and give some excellent advice. So a big thanks Magnus!

What next?

Well just like when I completed my first VCDX, I was already looking for another challenge. Luckily I have already found the next certification and am well on the way to submitting my application for the Nutanix Platform Expert (NPX).

The VCDX-DCV and VCDX-Cloud have both been awesome learning experiences and I think both have proven to be great preparation for my NPX attempt, so stay tuned and with a bit of luck, you’ll be reading my NPX Journey in the not to distant future.

Is VAAI beneficial with Virtual Storage Appliance (VSA) based solutions ?

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I saw a tweet recently (below) which inspired me to write this post as there is still a clear misunderstanding of the benefits VAAI provides (even with Virtual Storage Appliances).

vaaionvsatweet2

I have removed the identity of the individual who wrote the tweet and the people who retweeted this as the goal of this post is solely to correct what I believe is mis-information.

My interpretation of the tweet was (and remains) if a solution uses a Virtual Storage Appliance (VSA) which resides on the ESXi host then VAAI is not providing any benefits.

My opinion on this topic is:

Compared to a traditional centralised NAS (such as a Netapp or EMC Isilon) providing NFS storage with VAAI-NAS support, a Nutanix or VSA solution has exactly the same benefits from VAAI!

My 1st reply to the tweet was:

vaaionvsatweetconvojoshreply2

The test I was referring to with Netapp OnTap Edge can be found here which was posted in Jan 2013, well prior to my joining Nutanix when I was working for IBM where I had been evangelising VAAI/VCAI based solutions for a long time as VAAI/VCAI provides significant value to VMware customers.

The following shows the persons initial reply to my tweet.

vaaionvsatweetconvo32

I responded with the below mentioning I will do a blog which is what you’re reading now.

I went onto provide some brief replies as shown below.

repliesdetail

The main comments from this persons tweets I would summarize (rightly or wrongly) below:

  • VAAI is designed only to offload functions externally (or off the ESXi host)
  • He/She had not seen any proof of performance advantages from VAAI on VSAs
  • Its broken logic to use VAAI with a VSA

Firstly, I would like comment on VAAI being designed to offload functions externally (or off the ESXi host). I don’t disagree VAAI has some functions designed to offload to the (centralised) array but VAAI also has numerous functions which are designed to bring other efficiencies to a vSphere environment.

An example of a feature designed to offload to a central array is the “XCOPY” primitive.

A simple example of what “XCOPY” or Extended Copy provides is offloading a Storage vMotion on block based storage (i.e.: VMFS over iSCSI,FC,FCoE not NFS) to the array so the ESXi host does not have to process the data movement.

This VAAI primitive would likely be of little benefit in a VSA environment where the storage is presented is block based and Storage DRS for example was used. The data movement would be offloaded from ESXi to the VSA running on ESXi and host would still be burdened with the SvMotion.

However XCOPY is only one of the many primitives of VAAI, and VAAI does alot more than just offload Storage vMotions.

For the purpose of this post, I will be discussing VAAI with Nutanix whos Software defined storage solution runs in a VM on every ESXi host in a Nutanix cluster.
Note: This information is also relevant to other VSAs which support VAAI-NAS.

So what benefit does VAAI provide to Nutanix or a VSA solution running NFS?

Nutanix deploys by default with NFS and supports the VAAI-NAS primitives which are:

  • Full File Clone
  • Fast File Clone
  • Reserve Space
  • Extended Statistics

Note: XCOPY is not supported on NFS, importantly and specifically speaking for Nutanix it is not required as SvMotion will be rarely if ever used with Nutanix solutions.

See my post “Storage DRS and Nutanix – To use, or not to use, that is the question?” for more details on why SvMotion is rarely needed when using Nutanix.

For more details of VAAI primitives, Cormac Hogan (@CormacJHogan) wrote an excellent post which can be found here.

Now here is an example of a significant performance benefits of VAAI with Nutanix.

Lets look at Clone of a VM on a Nutanix platform, the VMs details are below.admin01vm

The VM I have used for this test resides on a datastore called “Management” (as per the above image) which presented via NFS and has VAAI (Hardware Acceleration) enabled as shown below.datastore

Now if I do a simple clone of a VM (as shown below) if the VM is turned on, VAAI-NAS is bypassed as the “Fast File Clone” primitive only works on VMs which are powered off.

clone

So a simple way to test the performance benefits of VAAI on any platform (including Hyper-converged such as Nutanix, a Virtual Storage Appliance (VSA) such as Netapp Ontap Edge or traditional centralised SAN or NAS) is to clone a VM while powered on then shut-down the VM and clone it again.

I performed this test and the first clone with the VM powered on started at 1:17:23 PM and finished at 1:26:12 PM, so a total of 8 mins 49 seconds.

Next I shut down the VM and repeated the clone operation.cloneresults

As we can see in the above screen capture from the 2nd clone started at 1:26:49 PM and finished at 1:26:54 PM, so a total of 5 seconds.

The reason for the huge difference in the speed of the two clones is because VAAI-NAS “Fast File Clone” primitive offloaded the 2nd clone to the Nutanix platform (which runs as a VM on the ESXi host) which has intelligently cloned the VM (using metadata resulting in almost zero data creation) as opposed to 1st clone where VAAI-NAS was not used which resulted in the hypervisor and storage solution having to read 11.18GB of data (being the source VM – Admin01) and write a full copy of the same data resulting in effectively >22GB of data movement in the environment.

Now from a capacity savings perspective, a simple way to demonstrate the capacity savings of VAAI on any platform is to clone a VM multiple times and compare the before and after datastore statistics.

Before I performed this test I captured a baseline of the Management datastore as shown below.

BeforeCloningCapacityVMcount

The above highlighted areas show:

  • Virtual Machines and Templates as 83
  • Capacity 8.49TB
  • Provisioned Space 7.09TB
  • Free Space 7.01TB

I then cloned the Admin01 VM a total of 7 times.clone7vmsrecenttasks

Immediately following the last clone completing I took the below screen shot of the Management datastores statistics.

AfterCloningCapacityVMcount

The above highlighted areas in the updated datastore summary show:

  • Virtual Machines and Templates INCREASED by 7 to 90 (as I cloned 7 VMs)
  • Capacity remained the same at 8.49TB
  • Provisioned Space INCREASED to 7.29TB as we cloned 7 x ~40Gb VMs (Total of ~280GB)
  • Free Space REMAINED THE SAME at 7.01TB due to VAAI-NAS Fast File Clone primitive working with the Nutanix Distributed File System.

So VAAI-NAS allowed a VM of ~11GB of used storage (~40GB provisioned) to be cloned without using any significant additional disk space and the clones were each done in between 5 and 7 seconds each.

So some of the benefits VAAI-NAS provides to Nutanix (which some people would term as a VSA type solution) include:

  • Near instant VM cloning via vSphere Client/s (as shown above)
  • Near instant Horizon View Linked Clone deployments (VCAI) – Similar to example shown.
  • Near instant vCloud Director clones (via FAST Provisioning) – Similar to example shown.
  • Major capacity savings by using Intelligent cloning rather than Full Clones (As shown above)
  • Lower CPU overhead for both ESXi hosts AND Nutanix Controller VM (CVM)
  • Ability to create EagerZeroThick VMDKs on NFS (e.g.: To support Fault Tolerance & clustered workloads such as Oracle RAC)
  • Enhanced ability to get statistics on file sizes , capacity usage etc on NFS

In Summary:

Overall I would say that VMware have developed an excellent API in VAAI and Nutanix along with VSA providers having support for VAAI provides major advantages and value to our joint customers with VMware.

It would be broken logic NOT to leverage the advantages of VAAI regardless of storage type (VSA, Nutanix or traditional centralized SAN/NAS) and for the vast majority of vSphere deployments, any storage solution not supporting (or having issues/bugs with) VAAI will have significant downsides.

I am looking forward to ongoing developments from VMware such as vVols and VASA 2.0 to continue to enhance storage of vSphere solutions in the future.

I hope customers and architects now have the correct information to make the most effective design and purchasing recommendations to meet/exceed customer requirements.

My VCAP5-CIA Experience

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Yesterday (21st July 2014) I sat and passed the VMware Certified Advanced Professional Cloud Infrastructure Administration (VCAP5-CIA) exam at my local test centre here in Melbourne, Australia.

As with the VCAP-DCA which I did as a prerequisite for VCDX back in 2011, the CIA exam is a live lab exam where VMware get you to demonstrate your hands on expertise with their products.

I find the value of the VCDX, is in part due to the fact it is a requirement to have not only “Design” but hand-on implementation/administration/troubleshooting experience as it is my opinion a person should not be an architect unless that person has the hands on experience and ability to implement and support the solution as designed.

So, enough rambling, what did I think of the VCAP-CIA?

As with all VMware certifications, the exams are generally well written and closely aligned to the blueprints which VMware provide. For VCAP-CIA the blueprint and exam registration can be found here.

The VCAP-CIA was no different, and aligned very well to the blueprint.

The exam is 210 minutes and has 32 questions some of which are simple 1 min tasks where others require a significant amount of work. One secret to all VCAP exams is you are challenged not only by the questions, but by the clock as time is the enemy. This makes time management essential. Do not get caught up of one question, if your unsure, do your best and move on.

Be ware some questions are dependant on successfully completion of earlier questions, but in saying that, a lot of questions are not, so don’t be afraid to skip questions if your struggling as you will still be able to complete many other questions.

The actual live lab in the exam consists of seven ESXi hosts, three vCenter Server virtual machine, four VMware vCloud™ Director (vCD) cells plus additional supporting resources. The lab has a number of pre-configured vApps and virtual machines will also be present for use with certain tasks. It is importaint to understand the lab environment is based on VMware vCloud Suite 5.1 and vCenter Chargeback Manager 2.5, not vCloud 5.5 so ensure you study and prepare using the correct versions of vCloud/vCB!

At this stage some of you may be thinking, I just breached the NDA telling the world about the exam? Well I haven’t and this is the beauty of how VMware does their exam blueprints, the above information is all available in the blueprint so there is not trickery or secrecy to the lab.

As for the questions in the VCAP-CIA, you will not get a brain dump out of me, but what I can tell you is the questions are in most cases very clear and what is asked of the candidates is vastly skills that anyone with any significant vCD experience would be familiar with. For example, the blueprint under Objection 1.2 – Configure vCloud Director for scalability, states under skills and abilities:

 Generate vCloud Director response files
 Add vCloud cells to an existing installation using response files
 Set up vCloud Director transfer storage space
 Configure vCloud Director load balancing

Its safe to say if you know the blueprint properly, you will be able to complete the tasks in the exam, and as a result, get a passing score.

Now the bad news!

Being based in Melbourne, Australia, and the live lab is being accessed by RDP to a location in Seattle, USA. So what does this mean, Latency!

I was only able to complete about 2/3rd’s of the questions in large part due to the delay in the screen refreshing after switching between for example the vCD web interface and production documentation, Putty etc.

On that point, all the PDF and HTML documentation is available in the exam, but I would highly recommend you don’t rely on it, because accessing the doco and searching/scrolling for things is very slow, at least it was for me.

I had numerous occasions where the screen would totally freeze which was a concern, but I soon accepted this was a latency issue, and the lab was fine, and waited out the freezes (which varied from a few seconds to around 20 seconds, which feels like hours when your against the clock!)

I have heard from numerous other VCAP-CIA who sat the exam in the Australia/NZ region that they experienced the same issues, so if you are A/NZ based, or any location a long way from the USA, be prepared for this.

Now being a live lab, the exam is not scored on the spot, and you have to wait for VMware to score the exam and then you will receive an electronic score report via email. The exam receipt says 15 business days, but I was very impressed that less than 24 hours after sitting the exam, I got my score report. Obviously VMware education have done a great job in automating the scoring process, which is a credit to them!

Overall, the experience of the VCAP-CIA was very good, the exam/questions are a solid test of vCloud related skills and experience, so great work VMware Education!

I am very pleased to have completed this exam and all prerequisites for VCDX-Cloud (VCP-Cloud, VCAP-CID and VCAP-CIA) and I will be submitting my application in the near future.