02.21.2010 - Top 5 Planet V12n blog posts week 07

Let me start by congratulating two well known community members with achieving the VCDX certification. Congrats Jason Boche and Scott Lowe, well done. These two guys just received the news that they passed the final stage and I am already been preparing the upcoming VCDX Defense Panels in Munich. Upcoming week is an exciting one for me personally, shifting jobroles... As of Monday I will be a vCloud Architect for VMware Advanced Services. My focus, in terms of blogging, will remain the same but of course will include more cloud related topics. But enough introduction blabla, let’s start digging into the top-5:

• Frank Denneman - Impact of host local VM swap on HA and DRS
  This rule also applies when migrating a VM configured with a host-local VM swap file as the swap file needs to be created on the local VMFS volume of the destination host. Besides creating a new swap file, the swapped out pages must be copied out to the destination host. It’s not uncommon that a VM has pages swapped out, even if there is not memory pressure at that moment. ESX does not proactively return swapped pages back into machine memory. Swapped pages always stays swapped, the VM needs to actively access the page in the swap file to be transferred back to machine memory but this only occurs if the ESX host is not under memory pressure (more than 6% free physical memory).
• Jason Boche - My VCDX Defense Experience
  During the days leading up to my defense, I felt very confident.  I had been studying my design and going over all the Enterprise Admin and Design exam study material on a daily basis.  I had been brushing up on white papers and blog articles for areas which I felt I was weak on or had forgotten details of.  I brought a 3 ring binder filled with about 400 pages of documentation as well as every VI3 published .pdf known to mankind on my thumb drive.  While I didn’t read all the .pdf files, they were with me if I needed them for reference.  As it turned out, a few of the documents I crammed on the night before my panel would play a nice role during part of my defense.
• Scott Sauer - Performance troubleshooting VMware vSphere CPU , Memory
  Watch pCPU0 on non ESXi hosts.  If pCPU0 is consistently saturated, this will negatively impact performance of the overall system.  If you are using third party agents, ensure they are functioning properly.  A couple of years ago we had issues with HP System Insight management agents (Pegasus process) which was creating a heavy load on our COS.  All of the virtual machines looked fine from a performance perspective, but once we dug a little bit deeper, we discovered this was our root cause.
• Gabrie van Zanten - Converting vscsiStats data into Excel charts
  Some time ago I wrote a posting on how to use vscsiStats to gather even more data from your VMs and their SCSI performance ( See: Using vscsiStats – the full how-to). Last week I received an e-mail from Paul Dunn who had written an Excel macro that can read the output from the vscsiStats exported csv file and convert it into Excel histograms.Using the macro is very straight forward. First you let vscsiStats run for a while and have it export the data to csv file. For example with the following command (Do pay attention to just one capital S in vscsiStats): /usr/lib/vmware/bin/vscsiStats -p all -w id -c > /root/vscsiStats-export.csv
• Simon Gallagher - The Computing Super-Powers are Aligning Their Stacks
  With HP’s recent acquisition on 3Com and their existing HP ProCurve range I would hazard a guess that they will stop selling Cisco blade switches in future – I also note from an email that all HP partners got this week that all Cisco manufactured blade switch components were facing supply issues, stoking the fires somewhat to resellers to push the HP product with some choice anti-Cisco FUD which I won’t repeat here.