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Top 5 Planet V12n blog posts week 06

VMware PEX 2010 was great… but it did mean I was extremely busy and didn't have time to create the top-5. I just picked the 5 best reads this week. Check it out:

  • Jason Boche – My VCDX defense experience
    The first 75 minutes is spent “defending” my design.  I’ve got about a
    15 slide deck to get through and to use as reference throughout the
    design defense.  I’d highly recommend putting as much reference as you
    can in the slide deck which you can yourself refer to during the
    defense.  It will help illustrate design choices and jog your memory
    for design elements which you’ve forgotten due to nervousness. The
    first 5-10 minutes I was pretty nervous and stuttered once or twice
    during my presentation. After that, I warmed up and it felt more like a
    good technical discussion with co-workers which I enjoyed.
  • Mike La Spina – Running ZFS over NFS as a VMware Store
    In this architecture we are defining a fault tolerant configuration
    using two physical 1Gbe switches with a quad or dual Ethernet
    adapter(s). On the OpenSolaris storage head we are using IPMP aka IP
    Multipathing to establish a single IP address to serve our NFS store
    endpoint. A single IP is more appropriate for VMware environments as
    they do not support multiple NFS IP targets per NFS mount point.  IPMP
    provisions layer 3 load balancing and interface fault tolerance. IPMP
    commonly uses ICMP and default routes to determine interface failure
    states thus it well suited for a NAS protocol service layer. In a
    effort to reduce excessive ICMP rates we will aggregate the two dual
    interfaces into a single channel connection to each switch. This will
    allow us to define two test IP addresses for the IPMP service and keep
    our logical interface count down to a minimum. We are also defining a 2
    port trunk/aggregate between the two physical switches which provides
    more path availability and reduces  switch failure detection times.
  • Hany Michael – vSphere In Motion: A Real-World Live Migration Scenario
    I was having a discussion with one of the large enterprises here in
    Qatar lately, and I was quite surprised to know from them that they are
    hesitated to migrate their VI3.5 environment to vSphere because of the
    associated downtime. What surprised me was not the fact that they can't
    afford a downtime, I've spent 6 years of my career working in the
    Telecom sector and I know for a fact that 1 second of downtime could
    mean a disaster, or even translate to a loss of thousand of $$. What
    surprised me was that they didn't know that it is possible to do this
    migration without any downtime!
  • Scott Drummonds – Inaccuracy of In-guest Performance Counters
    Every couple of months I receive a request for an explanation as to why performance counters in a virtual machine cannot be trusted. While it is unfairly cynical to say that in-guest counters are never right, accurate capacity management and troubleshooting should rely on the counters provided by vSphere in either vCenter or esxtop. The explanation is too short to merit a white paper but I hope a blog article will serve as the authoritative comment on the subject.
  • Bouke Groenescheij – Removevmha
    Today I've updated the popular removevmhba script to version 5.0. This version now includes the removal of the drivers in vSphere ESX 4.0 update 1 isos. Thanks to Dinny Davies who did excellent work again on finding a solution for removing them on vSphere ESX4 (he just beat me to it Wink). Check the original ESX 3.x.x version here, and the new ESX 4.x.x document here. Go ahead, grab removevmhba from the downloads section and give it a try. It removes the drivers only during installation, so you don't need to bother disconnecting your SAN or zone out anything during installation (both Emulex and Qlogic – and also hardware initiated iSCSI adapters). It's much safer for a scripted installation of ESX using the UDA or EDA. After the installation you will have the drivers (since it is installed as a package) – so you will get connection back to your SAN.
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Duncan Epping

About Duncan Epping

Duncan Epping is Chief Technologist working for VMware. Main responsibility is exploring new possibilities with existing products and features, researching new business opportunities for VMware. Duncan specializes in Software Defined Storage, hyper-converged infrastructures and business continuity / disaster recovery solutions. Duncan has 3 patents pending on the topic of availability, storage and resource management. He was among the first VMware certified design experts (VCDX 007). He is the co-author of several books, including best seller vSphere 5.1 Clustering Technical Deepdive. He is the owner and main author of the leading virtualization blog yellow-bricks.com.