VMTN Blog

It was one of those weeks again. I had a lot to do, and there is still a lot left to do. I just finished this top 5 and the quality of the articles is again very high. Especially Chad's article, wow... Anyway, start reading and enjoy. This is my gift to all fathers out there.

• Mike Laspina - Automating vSphere ESX4 Host Installations
  The custom VMware kernel incorporates Linux kickstart scripting functionality to invoke automated installations. The script location is defined as part of the Syslinux functionality and is available as a menu at boot time. A control file located on the boot media provides these variable control elements. Depending on the media type Syslinux uses a respective cfg file to implement this function. The various available Syslinux boot methods that I am aware of are USB, CD, DVD, PXE and gPXE. In this blog I will demonstrate an ISO CDROM method to perform the automated boot cycle. Any of the boot methods mentioned will all work and have varying levels of complexity to achieve.
• Chad Sakac - VMware I/O queues, “micro-bursting”, and multipathing
  A shallow queue somewhere in the IO path (or an overflowing port buffer) will cause the I/O to back off.    You need the queues to be deep enough to withstand the bursts – sometimes increasing the queue depth is important.   Now, if the problem isn’t actually the bursts, but the I/O service time not being sufficient for the sustained workload (aka you have a slow, or underconfigured array), increasing the queue depth will help for only a fraction of a second, after which the deeper queue will still fill up, and now you just have increased the latency even more.
• Bouke Groenescheij - Queue Depth and more
  Last few weeks we have had some issues regarding our HDS USP-V. For some reason a SCSI lock locked the whole VMFS and all ESX servers in that cluster were not able to read/write to the VMFS anymore. The LUN was still available, however the VMFS not. So this crashed all the VMs in the cluster. The incident repeated itself after 6 weeks, on another server, other chassis, other switches and so we contacted VMware and HDS to help us in this situation.
• Duncan Epping - VCDX Defense, the blog article
  The last part of the VCDX certification is the defense. In short: you will need to write a design, fill out the application and defend your design during a two to three hour session. Although I can describe it in 30 words it is not as simple as it may sound. First of all your design needs to meet specific requirements. I can’t go in to the details unfortunately but when you receive an invitation you will receive all the prerequisites. Like me, most of you done numerous designs, but keep in mind it needs to be in English and so will your defense need to be. This is an extra barrier for many of the non- native speakers; I know it was for me.
• Rodney Haywood - VMware vShield
  You can think of vShield as providing firewalls inside your ESX hosts. Each host runs one or more vShields which is a VM (provided as an OVF) which acts as a bridge between the real network and your Virtual Machines. These numerous vShield machines are all managed by a central vShield Manager (also provided as an OVF, one per vCenter Server). The vShield creates two zones, one protected and the other unprotected. The traffic enters the protected zone from the unprotected zone. As it crosses the zones the vShield performs traffic analysis, discovery and stateful firewall protection.