VMTN Blog

It was VCDX Defense week this week in Frimley and there were several panels scheduled. I met some cool people and learned a lot during this week. Next week there are VCDX Defense panels in Munich! If you are working towards VCDX, don't forget that panels normally are only scheduled around VMware Events. This means that there are only a couple times per year you can get certified. Blog wise there were a lot of great posts again this week. It was hard to pick only 5, but I did manage to do so:

• Frank Denneman - Lefthand SAN – Lessons learned
  Blocks will be stored on storage nodes according to replication level. If a LUN is created with the default replication level of 2-way, two authoritative blocks are written at the same time to two different nodes. If a 3-way replication level is configured, blocks are stored on 3 nodes. 4-way = 4 nodes. (Replication cannot exceed the number of nodes in the cluster) SAN IQ will always start to write the next block to the second node containing the previous block.
• Duncan Epping -  Slot sizes & Alan Renouf - HA Slot size information
  Five hosts, each host has 16GB of memory except for one host(esx5) which has recently been added and has 32GB of memory. One of the VMs in this cluster has 4CPUs and  4GB of memory, because there are no reservations set the memory overhead of 325MB is being used to calculate the memory slot sizes. (It’s more restrictive than the CPU slot size.) This results in 50 slots for esx01, esx02, esx03 and esx04. However, esx05 will have 100 slots available. Although this sounds great admission control rules the host out with the most slots as it takes the worst case scenario into account. In other words; end result: 200 slot cluster
• Eric Siebert - New Twitter lists for the top bloggers and VMware/Virtualization people
  Twitter is a great tool for communicating with other virtualization professionals, but trying to find interesting people to follow especially if you are new to Twitter can be time-consuming and difficult. For that reason I put together some Twitter group lists to make following people that are related to VMware virtualization easier. The first list is just from my Top 20 blogger list on my vLaunchpad that was decided by a poll I did months ago, consequently that one was really easy to put together. The second list is the top 100 people to follow that are related to VMware & virtualization, this one wasn’t easy at all to put together. The list started at about 300+ people that was part based on my followers and followings of other popular virtualization bloggers. Once I discovered that TweepML had a limit of 100 people I had to really trim that list down a lot, that wasn’t an easy task, especially the last 20 or so. There were some people I really wanted to keep on there but was forced to remove, the 100 person limit made for some difficult decisions.
• Hany Michael - vSphere 4.0 vNetwork Distributed Switch (vDS) - Video Demonstration + Architecture Diagram
  The diagram reflects the exact configuration on the video. I’ve done this intentionally to make it easier and faster for any one new to the vDS to understand the concept and the various configuration aspects. As I mentioned above, due to the very short period of time that I had, I will most probably modify small parts in the diagram to achieve better results. You can come back and check the version number of the diagram to download the latest updates.
• Scott Drummonds - Top Five VROOM! Entries for 2009
  I love VMware’s performance blog, VROOM!  It is our most popular performance communication vehicle and its content is backed by a stellar engineering team with unmatched integrity.  Each article details the nuances of VMware performance and educates on application and platform best practices.  I love all the articles but am always surprised as to which our readers find most popular.  Here is a countdown of the five entries most read in 2009.