Yellow Bricks

by Duncan Epping

vcdx

VCDX Prep Workshop Powerpoint published…

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Just got noted that the Presentation of the VCDX 3 Preperation Workshop has been published. This Powerpoint presentation was given by John Arrasjid and Pang Chen during Partner Exchange and got a lot of great feedback. For everyone aiming to become a VCDX over the course of the upcoming months this is definitely a must read!

VCDX Defense Preparation

Preparation time
  • Plan on working a minimum of 30-40 hours to complete the application and supporting documentation.
Mandatory VDCX documentation
  • Architectural design document with diagrams and blueprints
  • Implementation and next steps documentation
  • Validation/test plans
  • Operational plan/guide
  • Installation and configuration instructions

VCAP is nice, but what about VCDX 4?

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Looking at the VMware education website you can guess what the steps are to become a VCDX4:

VCP4 → VCAP4-DCA → VCAP4-DCD → Approved Design → Successful Defense = VCDX4

Please keep in mind that I am just guessing here, and this is not an official statement. Updates on the VCDX section of the VMware website can be expected any time soon now. The big question of course is what about those who are already certified? What will the upgrade path be? Honestly, I don’t know… we will just have to wait and see.

[UPDATE]

The info has just been released (Thanks Eric “scoop” Sloof) and I guess I was right:

  1. Be a VMware Certified Professional on vSphere 4 (VCP4)
  2. Pass the VCAP – Datacenter Administration Exam
  3. Pass the VCAP – Datacenter Design Exam
  4. Submit a VCDX4-DCD Application that is accepted
  5. Successfully present and defend a VMware Infrastructure Design and Implementation Plan

The following VMware advanced courses are recommended for VCDX certification preparation but are not required:

VCDX Application Form

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I had many questions around this and was always told I was not allowed to “talk” about the Application Form and the requirements for the VCDX defense. Apparently this has changed as VMware just published it on MyLearn and it is available to anyone with a MyLearn account.

Now, I want to remind everyone that this Application Form is subject to change:

The final step in becoming a VMware Certified Design Expert is the VCDX Defense. In this step you will need to successfully complete an interview, project review, and design defense activity. The VCP3 certification, the VMware Enterprise Administration on VI3 Exam pass, and the VMware Design on VI3 Exam pass are all pre-requisites to theVCDX Application. Applications will not be accepted unless all pre-requsites have been met.

Anyone going through the process will benefit from reading the application form. The questions I had most where what the minimal set of deliverables are. Those can be found in the application form, but for your convenience have been listed below:

  1. VI Architecture Design. This document provides a complete design for the virtual inf rastructure and dependencies. It provides detailed specifications for all architectural components, as well as the decisions and justifications behind design choices. It includes architectural schematic diagrams (a.k.a Design Blueprints)
  2. VI Installation and Configuration Guidelines and Procedures. This document provides guidance on how the specified design will be put together. This document i s sometimes referred to as an “assembly and configuration guide.”
  3. VI Operational Verification. This document provides a test plan t o be used to validate an implementation using the design documents.
  4. VI Operational Procedures. This document provides steps and guidance on how to use an implemented architecture from an operator’s perspective. This document is sometimes referred to as “standard procedures.”
  5. Next Steps. This document summarizes design requirements, objectives and issues. It provides recommendations for proceeding with the implementation as a wrap-up to a typical design project.

If you are going through the process, read the application form! Keep in mind that filling it out will take time. Especially the section on Design Decisions where you will need to come up with a consideration, decision, justification and impact in several sections of which for instance Storage, Networking, Cluster Design and VM design.

For those who will be submitting their design: READ! If it say “a minimum of four” stick to that as anything less is a straight reject.

VCDX defense panels

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Just to let you guys know… VCDX defense panels are being scheduled. The invites for Melbourne went out this week and the ones for VMworld SF will follow soon I guess.

Defense interviews will be held during the following days:

  • July 5-9, Melbourne, Australia
  • August 23-27, San Francisco, CA
  • October 11-15, Copenhagen, Denmark
  • November (dates TBD), Boston, MA

Completed applications will be scheduled in the order received.

source

Aligning your VMs virtual hard disks

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I receive a lot of hits on an old article regarding aligning your VMDKs. This article doesn’t actually explain why it is important but only how to do it. The how is not actually as important in my opinion. I do however want to take the opportunity to list some of the options you have today to align your VMs VMDKs. Keep in mind that some require a license(*) or login for that matter:

First let’s explain why alignment is important. Take a look at the following diagram:

In my opinion there is no need to discuss VMFS alignment. Everyone, and if  you don’t you should!, creates their VMFS via vCenter which means it is automatically aligned and you won’t need to worry about it. However you will need to worry about the Guest OS. Take Windows 2003, by default when you install the OS your partition is misaligned. (Both Windows 7 and Windows 2008 create aligned partitions by the way.) Even when you create a new partition it will be misaligned. As you can clearly see in the diagram above every cluster will span multiple chunks. Well actually it depends. I guess that’s the next thing to discuss but first let’s show what an aligned OS partition looks like:

I would recommend everyone to read this document. Although it states at the beginning it is obsolete it still contains relevant details! And I guess the following quote from the vSphere Performance Best Practices whitepaper says it all:

Src
The degree of improvement from alignment is highly dependent on workloads and array types. You might want to refer to the alignment recommendations from your array vendor for further information.

Now you might wonder why some vendors are more effected by misalignment than others. The reason for this is block sizes on the back end. For instance NetApp uses a 4KB block size (correct me if I am wrong). If your filesystem uses a 4KB block size (or cluster size as Microsoft calls it) as well this basically means every single IO will require the array to read or write to two blocks instead of 1 when your VMDK’s are misaligned as the diagrams clearly show.

Now when you take for instance an EMC Clariion it’s a different story. As explained in this article, which might be slightly outdated, Clariion arrays use a 64KB chunk size to write their data which means that not every Guest OS cluster is misaligned and thus EMC Clariion is less effected by misalignment. Now this doesn’t mean EMC is superior to NetApp, I don’t want to get Vaughn and Chad going again ;-), but it does mean that the impact of misalignment is different for every vendor and array/filer. Keep this in mind when migrating and / or creating your design.