VCAP5-DCA Testing Strategy and Tips

This year at VMworld in San Francisco, the #vBrownBag crew was able to host a series of Lightning Tech Talks, a series of 10 minute presentations in the HangSpace Community Stage. I was lucky enough to do two of the presentations, discussing testing strategy for the VCAP5-DCD and the VCAP5-DCA. This post will outline my presentation on the DCA. All of the presentations were streamed live and recorded. They should be available soon on:

If you are interested in taking the VCAP5-DCA, there are several resources out there that will help you tackle the technical aspects of the official blueprint. A few of them are listed below, and I recommend that you go over them during your exam preparation.

First and foremost is the #vBrownBag training series. These guys support an amazing site, hosting weekly webcasts on vSphere training. They record each presentation which can be downloaded from their website or iTunes. If you haven’t gone there or attended a #vBrownBag presentation, it is well worth your time on a Wednesday evenings at 7:30 CST. You can find all of the recordings here.

Jason Langer (@jaslanger) and Josh Coen (@joshcoen) have a great study guide at:

Gregg Robertson (@GreggRobertson5) has a guide here:

Chris Wahl (@chriswahl) has a study sheet here:

And finally, my own testing experience from the VCAP4-DCA

While there are several good site outlining the content, there are not many resources out there that will help you take the exam. The VCAP-DCA is 4 hours in length. While that sounds like a long time, most people that attempt the exam do not complete it in the time allotted. With the right approach to taking the exam, you should be able to efficiently work your way through the questions and wrap up your lab with time to spare.

Let’s look at the structure of the lab and understand the way that it is organized. When you begin the exam, you will be presented with a remote session to the Exam datacenter. You will have your workstation, RDP to a vCenter server, the vSphere Client, Documentation in PDF format, and such. You will be able to access your virtual lab environment and perform any functions or operations that the exam requires. On your test workstation, you will have the Exam interface. This is where all 26 questions will be located. Each question will require you to perform some task within your lab. Don’t worry about writing down any usernames or passwords. They are shown on every desktop and easily accessible.

I mentioned that there are 26 questions on the exam. If you check the DCA blueprint carefully, there are 26 sections that you need to cover. I’m not saying that there is a question on every section… What I AM saying is that one section of the blueprint is no more important or less important than another. It is there for a reason, so my advice is to learn each section to your best ability before scheduling the exam.

When you sit down in the Testing Center, you will be given a plastic coated page and a dry erase marker. In previous exams, I have simply left them unused during the test. This time, they may be your best friend.

When the exam starts, read question 1. Take your dry erase board, and number down the left side, 1 through 26. After 1, write a brief (2-3 words) description of the task described in question 1. Select the ‘NEXT’ button and progress to question 2. Read the question and write a brief description after the 2 on your board. Repeat this process until you reach the final question. After writing the last description, move backwards through the question until you reach question 1 again. You have now outlined all of the tasks involved for your examination, and the process should take no more than 10 minutes.

Your next step should be to evaluate each task and description briefly. Based on the DCA Blueprint, there are two distinct types of tasks involved in this exam, ‘Create’ and ‘Administer’. The ‘Create’ tasks involve building or modifying your lab environment in a manner that makes it possible to perform the Admin tasks. For example, before you could evaluate or optimize the performance of an Air Conditioner, you would probably need to purchase and install the AC unit in your house.

Go down your list of questions and tasks, and mark them with a ‘C’ or an ‘A’, indicating that they are either Create or Build tasks. This should only take about 3-5 minutes at the most. When you are done with this, you are ready to start the actual testing phase of the DCA.

Here is where my recommendations are a bit different from most others out there. I recommend that you start performing the Create tasks, one by one, and skip over the Admin tasks at this time. Why would you do this? Because sometimes the tasks involve processes that run on vSphere hosts, Windows servers, or the shared storage earmarked for your test lab. Some of these processes take time to complete, and if you sit there watching a server reboot, YOU ARE WASTING TIME!!! Additionally, for you to perform ‘Admin’ tasks in your lab, there is a good chance that you will need to have a piece of your lab in place (‘Created’), in order to complete the task. Try to complete all of your ‘Create’ tasks before tackling the bulk of the ‘Admin’ ones. Remember, if the lab doesn’t exist, how can you administer or evaluate it?

The goal of this exam is to test your administrative skills in a vSphere environment. Don’t waste time watching progress bars. If you have launched a process that you know will take 3-5 minutes or longer to complete, leave that process alone and move to another question. If the next ‘Create’ task is one that is dependent on the current task, switch gears and move backward in the question stack to one of the ‘Admin’ tasks. Fill in that empty time with a useful task.

Complete the ‘Admin’ task you have selected, and return to the ‘Create’ task you left earlier. If you are finished with a task, draw a line through the task on your dry erase board to keep a running tally of what you have left and what you still need to accomplish. This is the only time that you should perform ‘Admin’ tasks until you have completed all of your ‘Create’ tasks. During your exam, you may have several of these pauses in the ‘Create’ process in which you can tackle an ‘Admin’ task. However, keep an eye on the timer in the top corner of the window. Don’t get drawn into a task if it is taking too much of your time. Move along to another task and keep working. It is better to complete 24 out of 26 tasks, skipping 2 that took too much time than it would be to only complete 14 tasks because number 15 was not working as you expected. Move along and capture as many completions as you can.

When you are done with your ‘Create’ tasks and the lab is finished, move onto the remaining ‘Admin’ tasks. One advantage to this methodology is that most of the ‘Create’ tasks build upon each other. By the end of the exam, your lab will be completely fleshed out. The ‘Admin’ tasks usually aren’t dependent upon each other. The various ‘Admin’ tasks rely on the ‘Create’ tasks, but not each other. Here is where you can make up some time, based on your own personal strengths and weaknesses. Browse through the ‘Admin’ tasks and select one that is relatively simple for you to accomplish. This may be question 22 or question 3, and it usually won’t matter which order you work on them. My advice is to get as many out of the way that you are comfortable with first, before tackling other ‘Admin’ tasks that you are not as skilled performing. If you aren’t good at scripting or CLI tasks, don’t try to do those first and waste time researching and debugging a script. Move along to a different task. If you have extra time at the end of the exam, return to that difficult task and try to complete it. If time runs out, at least you didn’t miss completing your more familiar tasks.

Hopefully this will give you an advantage when attempting the VCAP5-DCA. Sometimes it isn’t what you know or don’t know that trips you up, but how you approach the game that makes the difference. Good luck!

Posted in certification, VCAP-DCA, VCP, virtualization, vmware | Tagged , , , | 16 Comments

Disaster Recovery and VMware, Pre-SRM

A new customer asked me today if I had any experience with Disaster Recovery, and if I was familiar with VMware’s Site Recovery Manager product.  My Sales Associate said “Of course he knows it, He invented SRM”.  I had to correct him, that I did not invent SRM.  However, I was involved in a co-hosted DR project between my former employer, Bowdoin College in Maine, and Loyola Marymount University in Los Angeles.  Out of curiosity, I searched Google and found an old video that I shot at VMworld 2006 in Los Angeles.  This video outlines our co-hosted DR project.  This video, followed by a lengthy interview at the Palo Alto campus with the DR group was followed up at VMworld 2007 in San Francisco with a mention in Diane Greene’s keynote and subsequent announcement of Site Recovery Manager.

Anyhow, here’s the link to the interview.  I know, it’s pretty cheezy.  Don’t blame me… VMware did all the post-production work!

VMware and Disaster Recovery at Bowdoin College

Posted in DR, Uncategorized, virtualization, vmware | Tagged , , | 3 Comments

VMware ColdClone utility

If you are a SysAdmin using VMware or work with customers in a virtual environment, you have more than likely performed a Physical-to-Virtual (P2V) migration.  In most cases, the free VMware Converter will perform  nicely here by imaging the physical server, adjusting components such as CPUs, memory, or drive sizes, and substituting virtual hardware for the physical components.  This is a very straightforward piece of ‘magic’ that has been the mainstay of virtualizing datacenters for years.

However, there is a piece of the puzzle that has been left out of the SysAdmin’s virtual toolkit for a few years.  If you go back several years, to the VMware Converter v3.03, there was a bootable iso version of the Converter available.  This utility allowed a SysAdmin to boot to the CD, load the Converter into memory, configure the local network, and image the server directly into a VM.

The greatest advantage to this utility was the fact that the server was shut down and offline.  It allowed you to capture the server with the OS completely quiesced, with no open files, or application conflicts.  If the server was on a different network segment than the vSphere hosts, simply connect it to the correct network with the server down and set the IP from the boot image without changing the server OS settings.  There was great advantages to having this CD in your laptop bag.

Alas, all good things come to an end.  VMware stopped supporting and updating the ColdClone image, and eventually dropped it from their website for download.  There is a rumor that it can still be found in the archives and copies are on shelves in the VMware ‘SkunkWorks’ labs.

Fortunately for me, I still have a copy or two stashed away on portable hard drives, burned to CDs, and such.  Sometimes it pays to be a software ‘PackRat’.

Additionally, I have taken other steps, like putting it up on my GoogleDrive so I can access it from anywhere.

Posted in P2V, virtualization, vmware | Tagged , , | 14 Comments

Recover a VM from the vm–flat.vmdk file

Last week I was onsite with a new customer, spending some time familiarizing myself with their existing infrastructure.  They are running vSphere 4.1 on Dell servers and EqualLogic storage.  While the hardware layout was solid and installed well, it quickly became apparent that the SysAdmin was a duck out of water.  There was a knowledge and comfort gap that could cause problems down the road if he became careless.  Little did I know that ‘down the road’ would be 2 hours later.

As the next few hours progressed, I found that he was using BackupExec agents within his critical business applications (2 VMs) and backing up directly.  The rest of his VMs were unprotected other than EqualLogic snapshots.   I pointed out to him that his snapshot schedule created one snapshot per hour, keeping 12 snapshots.  This protected him for less than one day.  He was at significant risk, and I recommended a more aggressive snapshot schedule as well as a more comprehensive backup plan.

We covered several other topics over the next few hours such as vMotion, Storage vMotion, and basic VM operations.  As I prepared to leave, he decided to perform a few Storage vMotion operations on VMs he had renamed, causing mismatched folder names within the datastore .  One of them happened to be his Domain Controller, which I will call ‘MismatchDC”.  When he tried to migrate to another datastore, vCenter threw an error stating that “the file mismatchDC-vmdk could not be found” and shut down the VM.  Within minutes, his phone was exploding with calls.  Nobody could login or get Exchange email.  He had pooched his Domain Controller.

While panic set in around his office and he was scrambling around, I opened up a datastore browser and was shocked.  Apparently the SysAdmin had deleted some ‘unnecessary files’, such as the VMX, VMDK, and everything else except the NVRAM and mismatchDC-flat.VMDK file!  These remained simply because they wouldn’t delete when he tried to delete them.

A quick check of the EqualLogic snapshots determined that he deleted these more than a day ago and they were not available, I also found that the Domain Controller was not on the list of ‘critical servers’ that they were protecting with BackupExec agents.  There was no way to restore this VM!  He started making plans to build a new VM s a DC, run DCPROMO, and sync across the WAN from his second site on the other side of the country.

As he was making his recovery plans and trying to explain to his boss how they would be down for the rest of the day, I recalled that I had read a KB article a while ago about recovering from a flat.vmdk file.  After a quick collaboration with my friend Google, I found it.  While it didn’t exactly fit my needs, it was enough to get rolling.  I took the size of the flat.vmdk file, divided by 1024, and divided by 1024 again to get the size of the VMDK in GB.  Luckily it came out to 25 on the nose.  Assuming that it was Win 2k3 server with a 25 GB drive, and the SysAdmin verified this from memory, I created a new VM called Temp as a Win2k3 server with 1 vCPU, 2 GB RAM, and a 25 GB HDD.

I enabled remote SSH, and logged in via Putty.  I went to the mismatchDC folder to verify contents.

cd /vmfs/volumes/vmfs01/mismatchDC/

I was correct in finding only the mismatchDC.nvram and mismatchDC-flat.vmdk files there.  I then moved over to the Temp VM location.

cd ../temp/

and found the temp-flat.vmdk file.  I renamed this to prevent it from being overwritten.

mv temp-flat.vmdk temp-flat.vmdk.old

Next, I copied over the original flat file and renamed it temp-flat.vmdk

cp /vmfs/volumes/vmfs01/mismatchDC/mismatchDC-flat.vmdk temp-flat.vmdk

When finished, I simply attempted to start the Temp VM.

As it started up, I saw the familiar Windows 2003 server splash screen, and called the SysAdmin over to verify that it was working.

After a few minutes of evaluation, it was proven that the Domain Controller was back up and running with less than an hour of data loss.

Steps to recover a VM from just the flat.vmdk file:

  1. Build new temp VM with EXACTLY identical vmkd file size
  2. Connect via CLI
  3. Rename temp-flat.vmkd file
  4. Copy existing-flat.vmdk file and rename to temp-flat.vmkd
  5. Power on temp VM

Lessons Learned:

  1. Backup your Servers, physical or virtual
  2. Snapshots are NOT backups
  3. Don’t delete things you don’t understand

VMware KB article 1002511


Posted in backups, DR, equallogic, virtualization, vmware | Tagged , , , | 13 Comments

Overcoming PowerPoint – Virtual Whiteboarding

How do you whiteboard to an audience of 200+ people without a whiteboard?
As a Solutions Architect, my job entails not only giving presentations to customers, but also at Lunch & Learn sessions and at conferences. It is very important for me to be able to pass on information, concepts, and design decisions to groups of various sizes. I noticed that more I used PowerPoint, the less engaged my audiences became. Somewhere, there was a disconnect between content and delivery. People glanced at the screen, then check their phones, email, or whisper among themselves. At first I thought it was me, but i noticed the same behavior when I was an audience member. I realized that I was guilty of the same behavior as well. I needed to mix things up and get the audience engaged again.
Last year I changed things up by getting rid of PowerPoint and bringing in a couple of whiteboards to a lunch presentation. By eliminating slides, the audience had to pay attention while I was talking. I used the whiteboard to illustrate my ideas and to expand the discussion. It was a resounding success, with attendees telling me that it was one of the best presentations they had ever seen.
Since that event, I have not delivered a PowerPoint presentation. I have exclusively used whiteboards when speaking to an audience. While there have been a few logistical issues, such as getting whiteboards where none exist, the results have been outstanding. Yet my greatest obstacle to date was approaching.
I was scheduled to present at a conference in Seattle to an audience of over 200 people, in a room that was too large for all attendees to see a whiteboard. If I couldn’t overcome this obstacle, I would be forced back to a slide deck.
I have an iPad, and occasionally use a whiteboarding application in small meetings. If I could figure out a way to extend this to a larger audience, I might still have a chance to do things my way. I purchased an AppleTV, and by using the AirPlay feature I was able to connect my iPad and my television via my home WiFi. I found a new whiteboard application, 2screens, that was AirPlay compatible. Bang! I could now project my iPad whiteboard to an audience. Since AirPlay requires a wired or WiFi connection between the iPad and AppleTV, and I could not be assured of signal at the conference, I decided to use my iPhone as a access point to connect the two. It was now time to put my design to the test in front of a live audience.

I was slated to give a presentation on VDI Performance in Seattle last week, and brought along my AppleTV, iPhone, and iPad. With everything set up and the projector showing my whiteboard app for all to see, I was mic’ed up and started speaking while carrying my iPad. I was able to walkout among the audience, side to side, taking questions during the session. As I walked and talked, I used the whiteboard to illustrate my points. My drawings appeared instantaneously on the screen at the front of the theatre. As with my other whiteboarding sessions, I captured the attention of everybody in the room. My new “digital whiteboard” worked like a charm.
One other thought that came to me a few minutes ago. I am writing this post during a layover in Detroit heading home to Maine after a week in Seattle. I started this blog with a whiteboarding post almost a year ago… during a Detroit layover heading home from Seattle. Funny how things work out when you aren’t paying attention.

Posted in performance, powerpoint, whiteboard | Tagged , , , | 1 Comment

Building a portable vSphere lab

When you are in the business of delivering virtualization solutions to customers, it helps if you know what you are talking about. While that is pretty obvious in and of itself, there is a great deal of work required to stay on top of the technology and trends. In most cases, you need a lab to work in. Having a sandbox in which you can try out new technology becomes a critical piece to the training and educational process. More importantly, if you are studying for any advanced certifications, access to a lab is pretty much a requirement for success. This was where I did most of my studying and practice while preparing for my VCAP-DCA and VCAP-DCD exams.

I am fortunate enough to have two different labs in which to play. First is my Demo Lab at the Mosaic Technology office. I was granted an isolated port off our firewall directly to my lab, and a private VPN into that network. On that network I have a Dell M1000 blade chassis with two M610 blades, two R710 and one 2950 racked servers, several Dell switches and two EqualLogic iSCSI SANs. This affords me enough hardware to configure just about any possible environment or scenario physically. However, the nature of my job keeps me away from the office most of the time, with only 2-3 days per month onsite. I can still VPN into my lab and make changes as needed, test new solutions or offerings, and even integrate new hardware and products into the rack. But as we added features and products, it became less of a sandbox and more of a showcase. There wasn’t enough flexibility in the environment for me to extend my knowledge as needed.

As a result, I decided to take matters into my own hands. When it came time for me to get a new laptop, I leveraged our position as a Dell partner to select a Precision 6500 mobile workstation for my new PC. Large 17 inch display, dual i7 processors, and 4 memory slots gave me great flexibility. Additionally, there is room for a second internal hard drive. I purchased with 4 GB ram and a 250 GB SATA drive standard. I installed another 8 GB RAM to bring it up to 12 GB, and added a Seagate MomentusXT hybrid drive in the second slot.

Installation of VMware Workstation 7 gave me the horsepower I needed to build out a lab internally. To begin with, I configured the virtual networks to use two vlans, the first VLAN8 was set for NAT to the host as a LAN connection. VLAN9 was configured to be host-only for storage network. I copied over a basic Win2k3 and Win2k8R2 image, creating two VMs from the base images. On the Win2k3 server I installed Active Directory and DNS. The Win2k8R2 became my vCenter server. I then created two VMs, 5 GB in size, and installed ESXi 4.1 on each. Once configured, I joined them to vCenter. As shared storage, I chose NFS. From the Virtual Appliance Marketplace, I downloaded a Fedora VM, added a 100 GB second drive, configured it to export the second disk via NFS, and then mounted it to the ESXi hosts. I also downloaded the Celerra Simulator from EMC to act as an iSCSI target as well.

Here is what the network diagram looks like:

With this in place, I now have a vCenter lab that I can take along with me wherever I go. Since the Public network is NAT to the host, I have a virtual NIC on my laptop on VLAN8. Once the VMs are powered up, I can use the tools on my laptop to interface with the lab. I can SSH to the hosts or the NFS server, use my vSphere Client, or RDP into the vCenter server or DC as needed. This is a great little lab configuration that I carry with me all the time. If I need to troubleshoot a problem, or try out a new tool or application, I can install it into my laptop lab easily. While I won’t win any awards for performance, as everything is a VM running on a single hard drive, at least I can bring it up anywhere. On several occasions, I have fired it up onsite with a customer to try out a new configuration or demonstrate a concept. Nothing beats a live demo!

Anyhow, I hope that this inspires some of you to give it a try. Do you need to buy a couple of servers to build out a home lab? Not if you don’t want to. In most cases, a good laptop or a desktop will suffice.

Posted in certification, VCAP-DCA, VCAP-DCD, VCDX, VCP, virtualization, vmware | Tagged , , , , , , | 1 Comment

My VCAP-DCA experience

There is an old joke that starts out “What do you call the guy that finishes last in his class at Medical School?”  The answer is “Doctor”.

As bad as that joke is, it is kind of how I feel about my VCAP-DCA result.  In a previous post, I wrote about my VCAP-DCD testing experience.  I was pretty confident going into that test because I have been designing customer virtualization solutions for the past three years.  Design is a daily function of my job, and the DCD was a natural extension this.  However, since leaving Bowdoin College and joining Mosaic Technology, I have been removed from the day to day grind of administration of said virtual infrastructure.  And like most things in life, there is a bit of “use it or lose it” when it comes to the DCA side of things.  I have my test labs, both at home and at the office, but without daily reinforcement, things can slip.

With that in mind, passing the DCD was validation, but I approached the DCA in a different light.  I studied the VCAP-DCA blueprint, which I recommend highly.  More importantly, take a look at Sean Crookson’s VCAP-DCA index.  This not only follows the blueprint, but gives a great outline of not just the topics, but where to find the subject matter.  Read it, study it, practice it, and then do it all over again.  Take some time to review the BrownBag sessions that Cody Bunch hosts on  They were of immense help as well.  I took all of this into consideration, prepared for the exam, but went into it with low expectations.  I didn’t expect to pass, but instead get a good feel for where my weak spots were, and where I would need to improve.  Try my best, but prepare for the worst.

As to the actual exam… While I can’t divulge the questions or content, I can discuss the nature of what you will need to know in order to prepare yourself.  The exam is only 34 questions long, as opposed to the 113 questions in the VCAP-DCD, but it is a completely different format.  You are presented with a virtual lab environment, and from question 1 all the way to question 34, you are building upon that same vCenter datacenter.  Tasks you perform early are built upon as you progress through, and early mistakes can multiply quickly and spin out of control.  Some tasks are simple, such as creating a cluster, performing basic storage and VM configuration tasks, setting up switches and such.  However, the tasks become more difficult as the exam rolls along.  You will be asked to perform some operations that you may have never done before, or in a specific manner you are not accustomed to do them.  Be aware of what you are doing, and make sure that you FOLLOW ALL DIRECTIONS!  If it says to perform via vMA, don’t do it via the vSphere Client GUI!  You will notice that you can move forward and back between the questions without switching into the lab environment.  I discovered this about 10 questions in, when I needed to go back and fix something that I missed in an earlier question.  Once I did this, I quickly moved forward through the questions and wrote on my dry erase board things such as 15-performance, 16-network, 17-storage… (not real, but you get the picture).  I broke down what was needed, then went back and tackled the infrastructure pieces in order.  It was important to do this in order to ensure that I had enough time to finish the exam.  I then went back and performed the tasks that were ancillary, such as generating reports, logging, making specific changes, etc.  Core infrastructure first, data and tweaks later was my mantra.   I don’t know if it was a weighted score, but if it all works at the end, you must have done something right.  As it was, I did not complete all of the tasks. I hoped that my jumping around would count for something.

As far as what to expect, all I can say is know everything on the blueprint.  More importantly, if there is a task on the blueprint, make sure you know how to do it not only from the GUI, but via command line, vMA, and if possible…PowerCLI.  Don’t underestimate your ability to perform operations via command line.  Know how to do it without a GUI, and you will drastically improve your chances to pass the VCAP-DCA.

And in reference to the joke at the top of this post… I passed my VCAP-DCA exam on the first try.  With a passing score of…300!  Exactly what was needed to pass.  Therefore, as with number 100 out of a class of 100 at medical school, all that matters is that we both passed.  I am now certified as a VCAP-DCA to go with my VCAP-DCD.  Next on board is preparing a VCDX design submission, and hopefully defending in Frankfurt in February, 2012.


Posted in certification, VCAP-DCA, VCAP-DCD, VCDX, virtualization, vmware | Tagged , , , , | 1 Comment

My VCAP-DCD experience

After much procrastination, I decided to pursue my VCDX4 certification.  As most of you know, this means completing the VCAP-DCD and VCAP-DCA exams first.  I have been working with VMware for over 7 years and have my VCP on v3 and v4, so am familiar with the VMware certification path.  I moved from the end user community to a VAR as a consultant and engineer a few years ago, and have been architecting solutions for customers for several years now.  While I enjoy keeping up with the latest and greatest technology available, maintaining the base certifications for work has made it difficult to pursue my personal goals of advanced certifications such as the VCAPs and VCDX.  With the announcement of a final VCDX4 defense in Frankfurt in February, I realized that I needed to get myself in gear to have a chance at v4, or else throw everything into getting up to speed on v5 and lose my advantage working with v4.x at this point.

With this in mind, the first step was to get my VCAPs out of the way first.  I decided on the VCAP-DCD first, as my focus these days tends to be more on designing new environments or upgrading existing installations of vSphere.  My administration skills are good, but without a functioning production environment to maintain on a daily basis, I can only beat up on my test lab so much.  I figured that leading with my strong suit would give me an advantage.

The first step after scheduling my exam was to ask my good friend Google if he had any references out there that have been through the DCD before.  Forewarned is forearmed.  Some good sources come from Eiad Al-Aqqad, Sean Crookson, and Gregg Robertson to name a few.  And, of course, the VCAP-DCD Blueprint!  While the NDA prohibits us from discussing the actual information on the exam, I can pass along some of the info regarding the setup and organization.  Most of this info is out there either in blogs or on the official VMware websites, so I believe I can speak freely.

To begin with, this exam is NOT to be taken lightly.  Most of the recommended study information is the same being offered for the VCP exams.  While this information is important, it is not really what this exam is about.  Where the VCP was very technically detailed, focusing on numbers such as maximum memory, hosts, CPUs, and other bits of esoteric knowledge, the VCAP-DCD had very little to do with it.  Rightly so, the powers-that-be assume that since the VCP is a requirement you’ve already memorized it and they want to test your brain in a different way.  The VCAP-DCD is all about is design.  They want to know how you think when you are putting all of the pieces together.  It is good to know the maximum number of hosts in a HA/DRS cluster, but more importantly, given a set of customer requirements… How would you design an environment?  What kind of decisions would you make, and why would you choose A over B?  Man on second with no outs in the 8th… do you sacrifice him to third, and why?  Carolina whole pig BBQ or Texas beef ribs?  Those kinds of decisions are what you will be faced with during the –DCD, only about virtual environments and how to build/create them.

With several years under my belt designing customer environments, I was comfortable with the questions and my answers as the test went along.  Technically, my hands-on experience carried me through the exam.  If you are looking for a class or book to give you the answers you seek, you are looking in the wrong place.  Course work and memorization will get you only so far with the VCAP–DCD.  Without a good working knowledge of vSphere and experience with design decisions, you will be at a disadvantage.

The actual questions and answers were not the difficult part of the exam.  The time limit was the greatest challenge.  This exam is 113 questions long, with 5 design questions in the mix.  Those 5 questions are a huge hurdle.  If you haven’t done it yet, make sure you use the VMware VCAP4-DCD Design Tool Simulator before you take the exam.  These questions have a Visio-type interface, and without prior experience with the tool, you will waste valuable time familiarizing yourself.  These design questions take 10-15 minutes each, and with only 225 minutes for the whole exam, you are down to a little over a minute per question for the rest of the exam.  There are several ‘drag and drop’ questions that can be time sinks as well if you are not careful.  In a nutshell, you need to stay on task and mind your time during the exam.  Don’t get hung up on a difficult question, flag it for review and move along.  If you get through in time, go back during the review period and make your decisions.  If you don’t make it to the end, at least you will get through more questions.  I can’t state this enough… you need to make quick decisions.  I have a sneaking suspicion that one of the factors you are being judged on is not only your knowledge, but you quick you think on your feet (so to speak).  You either know it or don’t, and putting you in a pressure situation such as not having enough time to think things out will weed out some folks that don’t have the base design experience.  I was able to make it through with 9 minutes to spare, and didn’t run into any overly difficult time-sink type questions.  There is about a minute or so after the exam where I stared at the blue background screen… and then the window pops up congratulating me for passing the VCAP-DCD.  I got a 321, with a 300 being a passing mark.  I took a deep breath, not realizing until after that I had been holding my breath in anticipation.  With the VCAP-DCD behind me, I am now studying for the VCAP-DCA.  With any luck, I will get through it and begin my design submission for a VCDX defense in February.

Posted in certification, VCAP-DCD, VCDX, VCP, virtualization, vmware | Tagged , , , , | 2 Comments

DRaaS? The way of things to come

My week here at VMWorld 2011 has been quite hectic. With the recent release of vSphere 5, SRM 5, View 5, and all of the other Cloud offerings from VMware, it has been a whirlwind of activity. As I fly between breakout sessions and briefings, I try to keep things in order by tweeting. You can follow me at @timantz for more info. That being said, a colleague asked me “what is the most significant thing that I learned so far at the conference?” Even with all of the new information, it wasn’t a difficult choice. With the new SRM 5 release, VMware now offers vSphere Replication. This is a host-based replication service, installed as part of SRM, that uses a Linux vAppliance, the SRMC, to coordinate replication of VMs from existing datastores to a paired vCenter installation datastore. This process seeds the initial information to the datastore target, and then uses changed block tracking within the vKernel to pass only the changed blocks across to the DR site. Why is host-based replication an important feature? Because DR with SRM is now available to everyone by leveraging this feature. With host-based replication, there is no longer a need to rely on the storage vendor for replication. Users with different storage at two datacenters, say EqualLogic and EMC, can now protect their virtual environments through SRM. Heterogeneous storage infrastructure is no longer an obstacle. We can offer protection to every VM, regardless of what the underlying storage platform of choice. What is even more important… If SRM is storage agnostic now, why do you even need a datacenter as your DR site? With the addition of so many cloud providers in the virtualization space, you can now create a virtual datacenter in the cloud, provision tiered storage as needed, and replicate your VMs securely to your own public cloud. As long as you have the infrastructure in place, you can dial up the resources in event of an actual DR event. Today at VMWorld, Dell announced that they now can provide cloud virtualization resources. What could be better than ordering up a DR site from Dell, using host-based replication to protect your VMs with SRM, and in event of a disaster, a simple phone call can provide you with as much compute power as needed to run your infrastructure in the cloud. Can we say DR as a Service (DRaaS)?

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Hybrids are Bleeping Magic

I can’t state it enough.  When you are designing a virtual desktop environment, you need to correctly size the back end storage correctly.  I have been involved with several VDI deployments, VMware View in particular, and storage performance can make or break a successful deployment.  If you don’t believe me, take a look at one of my other posts here.  That being said, how are you supposed to scale your virtual desktop POC from 100 users to 1000 knowing that the impact to your storage I/O load will be going through the roof?  The quick and unqualified answer is Solid State Drives.  With ratings over 4000 IOPS per disk, they easily outpace 15k SAS drives rated for 180 IOPS and can take the 100-fold hit to your I/O without blinking.  The down side is most storage vendors are still only supporting 100 GB SSD drives, so capacity is a problem.  How does EqualLogic overcome the performance/capacity issue with SSD drives?  It’s Magic… It’s Bleeping Magic.

Last summer, EqualLogic released their Hybrid PS6000XVS.  This array combined eight 100GB SSD drives and eight 600GB 15k SAS drives within a single 16 drive enclosure.  A proprietary RAID type allowed each volume to be stretched across both sides of the array, both SSD and SAS.  The two sides of the array have different I/O and performance profiles, and the EqualLogic controllers are aware of the differences in capacity and performance.  When data is written to the Hybrid array, incoming data pages are tagged as ‘hot’ by the system.  This is a rating of relative activity of pages within the array.  Recent reads and writes to the data marks the page as ‘hot’.  As read/write activity tails off, the page becomes ‘cool’ and even ‘cold’ if the page hasn’t been accessed recently.  Write activity automatically mark a page as ‘hot’.

Since the EqualLogic controllers know that the SSD drives have a higher performance profile than the 15k SAS drives, the data is written to the highest performing area within the array, which is the SSD drive set.  Continued reads will keep the data page ‘hot’, but inactivity for a specific page will cause it to ‘cool’ off relative to other pages.  Once a threshold is reached within the array, the data page is then moved (on the fly) over to the 15k SAS side of the array but still within the same volume.

This process continues to occur as new data is written to the volume, leveraging the high performance of the SSD drives and the higher capacity of the 15k SAS drives to optimize data page placement within the volume.  If a data page that resides within the 15k SAS side of the volume is accessed for reads or writes, the temperature of that data page increases.  Once the temperature of a page on the 15k SAS drives rises above a page that resides on the SSD side, the two pages are swapped (on the fly), therefore optimizing data page placement within the volume.

As you can see above, the ‘colder’ pages move to the lower tier of storage, while the ‘hotter’ pages are migrated to the highest performing level.  This optimizes data placement within the array and grants SSD level performance for all of the data within the volume while extending capacity with 600 GB SAS drives.

When considering VDI rollouts and the increased performance demands that a View infrastructure requires, it is easy to see that the PS6000XVS Hybrid array is a welcome addition to the storage toolkit.  By leveraging a Hybrid array, we can easily provide +30 thousand IOPS within a single enclosure with a couple TB of capacity.   This is a game changer in the VDI world, and one you should consider, especially if you are using EqualLogic storage.  If you are deploying VDI without considering one of these Hybrid arrays, Caveat Emptor.

Posted in Desktops, equallogic, iops, iscsi, performance, VDI, View, virtualization, vmware | Tagged , , , , , , , , , | 4 Comments