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Monthly Archives: May 2009

Top 5 Planet V12n blog posts week 18

I have been on a holiday the last week and had to catch up in just a few hours… Which is impossible with little over 250 unread posts on Planet V12n. But I managed to to catch up and as you can see some of the new comers on Planet V12n actually made it to the list this week:

  • Arnim van Lieshout – ESX Memory Management part 1
    Scott Herold – Memory behaviour when VM limits are set
    I posted these two as one because Arnim's post is actually what caused the awesome follow-up by Scott Herold:
    The first question that keeps coming up is "Don't memory management
    methods only kick in when there is contention?"  My answer to this is
    two-fold.  First, I've only seen the VMkernel waiting for contention
    when looking at shares to determine priority, not to execute a method
    of memory savings/management.  Secondly, we need to define
    "contention".  In this particular case it is when a Guest OS needs more
    resources than the VMkernel can assign to it at a point in time.  This
    can be from a lack of available resources, or by forcing a restriction
    (like a limit) as to how much the VMkernel can give to a guest.  That's
    the one thing about a limit in VMware…  The limit is a hard limit. 
    There is no "If someone else isn't using it we will let you go above
    it", it's static and absolute.
  • Robbert Patton – Hardening the VMX File
    If you've been working with any of the VMware products for even a short amount of time, you've probably explored the .vmx file. This single text file stores almost all of a virtual machine's configurable parameters, and has several optional settings that are not available from the administration tools and must be added by hand to the file. In this tutorial, we'll explore a few parameters that can be used to eliminate some serious vulnerabilities with VMware Tools and lock down the communications channel between a guest VM and the ESX server hosting it.
  • Chad Sakac – Thin on Thin? Where should you do Thin Provisioning – vSphere 4.0 or Array-Level?
    With the new awesome thin provisioning GUI and more flexible virtual disk behavior (hallelujah – no more "clone/template=eagerzeroedthick”!) in vSphere, I’m getting more questions re: best practices when you have the choice of doing it at the array level or the VMware layer.

    This is covered in chapter 6 of the upcoming Mastering VMware vSphere 4.0 that Scott Lowe is authoring (more here). I’ve guest authored Chapter 6 for Scott. Chapter 6 is entitled – “VMware vSphere 4.0 – Creating And Managing Storage Devices”
  • Jason Boche – Force vCenter Server update to reflect .VMX changes
    Modifying .vmx files by hand is all well and good. Administrators have been doing since since for as far back as I can remember with VMware products. There is an annoying caveat with VMware vCenter Server however. Changes made by hand in the .vmx file may take a while to show up in the Virtual Infrastructure Client. For example, if I’m looking at a VM’s configuration summary in the VIC, and then modify the .vmx file to change the memory configuration from 256MB to 512MB, save and exit, nothing seems to happen in the VIC. I’m looking at the VIC and configured memory of 256MB is staring back at me. It may end up staying this way for quite some time.
  • Ken Cline – Consolidation ratios are yesterdays news
    Ever notice that when you talk to someone about virtualizating, it always seems to come down to, “So, what’s your consolidation ratio?” Everyone seems to care only about the number of virtual machines you can house on a single host system. While consolidation ratios are important, they’re yesterday’s news!
    Virtualization is about so much more than just shrinking the footprint (physical and carbon) of your data center. Think about it: What does virtualization really do for you? It encapsulates your workloads (servers) into a collection of files that are consistent, that are portable, that are uncoupled from hardware, and that can be copied from location to location.