Although these are typical question for vmware design exams, (vcap-dcd, vcix-dcv-design) they are fundamental in calculating available capacity given a specific number of tolerable host failures What percentage of cluster resources does your cluster still have to start VM’s in the event of a failure with x admission control reservation. In other words, after setting admission control (see […]
Category Archives: Miscellaneous
vcix-dcv-design math – Get admission control percentage
VMware are clear about the importance of setting admission control on vSphere clusters, and the preference of using the percentage calculation where possible A simple formula will help calculate for heterogeneous cluster* For example I have a 12 node vsphere cluster and want to tolerate the loss of 4 hosts 100 / <number of hosts […]
vSphere 6 dVS NIOC Bandwidth Control
Bandwidth control methods are changed in vsphere 6 distributed virtual switches with NIOC 3 System Traffic, Network Resource Pools, Network Shares, Reservations and Limits, Traffic Filtering and Marking, QaS, Cos Tagging, DCSP Tagging, Network Traffic Rules, System Traffic Types, System Traffic Qualifiers, MAC Traffic Qualifiers, IP Traffic Qualifiers, dVS ACLs… The following diagram helps see […]
VCIX6 DCV Design – Exam Preparation Workbook
Trying to keep track of what you have read in preparing for the advanced level design exam is a task in itself. I’ve created a downloadable excel file that contains objectives and hyperlinks as per blueprint 3V0-622 v1.2, published on 4 December 2015 VMware Certified Advanced Professional 6 – Data Center Virtualization […]
virtual machine – measure windows cpu performance when limits are applied
In the previous posts I wrote about virtual machine cpu limits not being exposed to the guest OS. This presents concerns for systems and application admins when investigating performance related issues The example vm has a cpu limit of 750 MHz, though neither the OS or vCenter are triggering alarms. Keep in mind; operating system cpu percentage values […]
virtual machine performance – high cpu ready lab
Application issues, undersizing a virtual machine, or applying a restrictive cpu limit can all result in cpu ready CPU Ready is the primary indicator of a cpu performance issue. Although it’s possible to create a cpu-ready alarm, every VMware admin needs to be able to recognize what the values mean. How much cpu ready is ok It is […]
virtual machine performance – add cpu ready alarm
High cpu ready values are probably the single most recognised sign that a virtual machine is having problems, whether due to application issues, or cpu undersizing, the vSphere admin should know about it. Setting an alarm for this is so simple and flushes out the bad boys. The suggested settings are from VMware, 20% and 40%*. […]