It took me a while to get around to booking it but I passed my VCP5 exam on the first attempt yesterday.
Back in 2009 when vSphere 4 was launched, I took the VCP4 exam much earlier. I was thinking last night why this was and I think it’s down to a change in circumstances. In 2009 I was freelancing and I felt it was advantageous to get my VCP4 as soon as possible. Working as I now do for a consultancy as a permanent employee, it’s not been as important for me to update to VCP5. That said, I did want to do it before the end of February to avoid having to take the “What’s New in vSphere 5” course.
Now I know that everybody else who has posted about their VCP pass has done this but I just wanted to note the various resources that I used in my preparations. Many of them can be found mentioned on Gregg Robertson’s blog (The Saffa Geek) where he has a page dedicated to VCP5 studying resources. Besides that though I just wanted to call out a couple of things in particular:
- Scott Lowe’s book “Mastering VMware vSphere 5” is a brilliant introduction and detailed reference to vSphere 5.
- VMware’s own product documentation and KB articles.
- Trainsignal’s VMware vSphere 5 Training – very useful for learning anywhere (I had the videos on my phone).
- My own lab
That last resource is not to be underrated. Nowhere else can you try lots of different configurations and break things with impunity. ANd that is almost certainly the best way to learn.
A final word on the VCP5… good luck.
Whilst doing the rounds in the VMworld Solutions Exchange, I got into a conversation about VMware certifications on VMware’s stand. I was there for quite a while and learned a lot about how VMware choose questions and tasks for their exams. It’s quite an involved process and one designed to ensure that a certain percentage of people sitting the exams are capable of answering each question.
Each question must be carefully considered and researched by a small panel of people before it is submitted in to a pool from which the exams are built. In the case of the VCAP-DCA exam, extra effort is required to automate the creation of a suitable testing environment / conditions for the task and, where possible, a mechanism for automatically marking those tasks is required.
So, all things considered, it shouldn’t come as a surprise that exam development and release can take some time. Indeed, when I pressed for a VCAP5-DCA exam release date I wasn’t given a direct answer. It will take as long as it takes to get it right. There was, however, a strong feeling that it should be possible to sit the exam (or at least book it) before the year is out.
“Don’t call me Shirley!”
I love that joke but “surely not” was my response when John Troyer’s email popped into my inbox this morning.
Since that time I’ve had a veritable deluge of congratulations from all quarters. Along with the award itself that means a lot to me so this is a big public thank you to everyone really, especially John Troyer and vExpert panel.
Obviously the bar has been set now. Time to get my bottom in gear.
Where do I begin?
I am so glad it’s over. It’s been a long time since I took an exam where I had to wait for the results. Maybe even 14 years! Even then though, I knew the exact date when the results were due. With the VCAP-DCA, VMware say that you’ll get your score within 10 business days. That’s not too precise (although thankfully not too long either) and in the end it was more like 13 business days since I actually took the exam.
So, what’s it like?
There’s a limit to what I can and will say about the exam. Three and a half hours didn’t seem like nearly enough to get through it all – I ran out of time. A contributory factor in that though was the equipment / environment used to deliver the exam. I am used to working with a certain amount of screen real-estate and I lost a bit of time working with the 1024 x 768 display that I had. If you’ve ever tried using the vSphere Client on such a display you’ll appreciate what I mean.
I can’t say much about the content of the exam. Cover off as much of the exam blueprint as you can and you should be ok.
Next up for me is the DCD exam. Or maybe the Desktop exams. There’s plenty to do!
Well, that one objective dealt with. Just another 30 odd to go.
Don’t forget that reading is not everything, you need to have done as much of this stuff as possible.
There are links to VMware’s product documentation throughout, be sure to be familiar with it as the language and methods that they use there should be the same as you’ll find in the VCAP exam – I hope.
To put an application into a virtual environment you must first understand its I/O requirements to make sure that it will perform adequately on the storage that you have configured. This is very much like the process of determining how much CPU and Memory resource an application will need – it’s a necessary step. Of course you can miss it out and in the majority of cases that won’t be an issue but to keep your finger on capacity management and to avoid possible problems it is best to follow a defined a repeatable set of steps.
It’s also useful to be able to profile the I/O workload of applications already on a virtual platform.
So, what do we need to know? Well although I have a fairly well-rounded set of skills, I am more of a Microsoft guy than a Unix guy. As such I’m better at looking at I/O on Windows systems than anything else. Obviously this is something that I need to address a bit but it’s not exactly in the scope of this post.
Kevin Kline, a SQL MVP, has a short video hosted here that is targeted at physical SQL servers – the kind of load you’re likely to want to do this with.
There’s also a good MS Technet article about determining the I/O requirements for Exchange 2003 that’s a useful read.
Next up, I’d suggest having a look at SWAT. It’s Sun’s java based I/O monitoring tool.
Also, get to know vscsistats. Scott Drummonds (a guru in this area) has a VMware communities page that is a must read. Next, read the useful posts by Duncan Epping (YellowBricks), Gabrie van Zanten (Gabe’s Virtual World) and Gabe’s other post on making the output data Excel friendly.
What is LUN masking? explains what LUN masking is in layman’s terms (in case you have a NAS only background). See Storage Masking? for the Yellow Bricks advice on LUN masking.
For an overview of PSA and commands, see VMware vSphere 4.1 PSA.
Also see the vSphere CLI guide, vSphere Command-Line Interface Installation and Reference Guide.
VMFS Resignaturing is worth a read. See also the section on Managing Duplicate VMFS Datastores in the ESX Configuration Guide.
From the ESX Configuration Guide.
When you perform VMFS datastore management operations, vCenter Server uses default storage filters. The filters help you to avoid storage corruption by retrieving only the storage devices, or LUNs, that can be used for a particular operation. Unsuitable LUNs are not displayed for selection. You can turn off the filters to view all LUNs.
Before making any changes to the LUN filters, consult with the VMware support team. You can turn off the filters only if you have other methods to prevent LUN corruption.
- In the vSphere Client, select Administration > vCenter Server Settings.
- In the settings list, select Advanced Settings.
- In the Key text box, type a key.
Key Filter Name
config.vpxd.filter.vmfsFilter VMFS Filter
config.vpxd.filter.rdmFilter RDM Filter
config.vpxd.filter.SameHostAndTransportsFilter Same Host and Transports Filter
config.vpxd.filter.hostRescanFilter Host Rescan Filter
NOTE If you turn off the Host Rescan Filter, your hosts continue to perform
a rescan each time you present a new LUN to a host or a cluster.
- In the Value text box, type False for the specified key.
- Click Add.
- Click OK.
You are not required to restart the vCenter Server system.
Read Performance Characterization of VMFS and RDM Using a SAN. It may be for ESX 3.5 but still holds true. The conclusion from the document is:
VMware ESX Server offers two options for disk access management—VMFS and RDM. Both options provide clustered file system features such as user‐friendly persistent names, distributed file locking, and file permissions. Both VMFS and RDM allow you to migrate a virtual machine using VMotion. This study compares the performance characteristics of both options and finds only minor differences in performance. For random workloads, VMFS and RDM produce similar I/O throughput. For sequential workloads with small I/O block sizes, RDM provides a small increase in throughput compared to VMFS. However, the performance gap decreases as the I/O block size increases. For all workloads, RDM has slightly better CPU cost.
The test results described in this study show that VMFS and RDM provide similar I/O throughput for most of the workloads we tested. The small differences in I/O performance we observed were with the virtual machine running CPU‐saturated. The differences seen in these studies would therefore be minimized in real life workloads because most applications do not usually drive virtual machines to their full capacity. Most enterprise applications can, therefore, use either VMFS or RDM for configuring virtual disks when run in a virtual machine.
However, there are a few cases that require use of raw disks. Backup applications that use such inherent SAN features as snapshots or clustering applications (for both data and quorum disks) require raw disks. RDM is recommended for these cases. We recommend use of RDM for these cases not for performance reasons but because these applications require lower level disk control.
And read Use RDMs for Practical Reasons and Not Performance Reasons too.
There is a section in the ESX Configuration Guide that is relevent.