vCenter Virtual Appliance Network Settings Reverting

In one of my lab environments my vCenter Server Appliance (VCVA VCSA*) kept reverting its DNS server settings after I changed them in the VCSA web interface (https://:5480).  After changing the Preferred DNS Server and Alternate DNS Server settings to use my Active Directory Domain Controller IPs and then rebooting the appliance, the DNS settings were removed and the Preferred DNS Server setting was reverted to the setting present before I updated it. Losing my DNS Server settings caused me all sorts of issues - my vCenter Server couldn't find ESXi hosts by name, AD authentication failed, … [Read more...]

PowerCLI Script to Set DNS and NTP on ESXi Hosts

Since joining VMware, I've built, rebuilt and updated several lab environments (home lab and work labs).  One of the problems I keep running into is incorrect/missing/disabled NTP on my ESXi hosts.  Because lab gear is often abused well-loved, BIOS time is not always correct (long periods of being powered off), settings are all sorts of jacked up (it's a lab, we're engineers, let's break stuff!!!), and documentation is non-existent.  The problem is not just in a lab environment - the number of customer environments I've seen that aren't set to use NTP is much higher than I would have thought … [Read more...]

CPU Ready Revisted – Quick Reference Charts

I've written in the past about how high CPU Ready values can cause performance problems in VMware vSphere environments.  For those who don't know, CPU Ready is a measure of the amount of time that a guest VM is ready to run, but the VMware ESXi CPU Scheduler on the host is not able to immediately allocate cycles to the guest because it is busy doing work for other VM's.  CPU Ready values are exposed through ESXTOP and in the vSphere Client. I'm often called into customer environments to do performance troubleshooting, and CPU Ready is one of the first performance measurements I check my … [Read more...]

Lag When Dragging a Window Between Monitors in VMware View

I've had several customers ask me for help with the VMware View environment recently, as their users were complaining about performance issues when dragging a window between monitors in a multi-monitor VMware View setup.   Performance was otherwise acceptable on the View desktops.  I recommended several troubleshooting and remediation steps to get windows to stop slowing down when dragging between monitors or "catching" on the border between the two screens, including: Review the "Multimonitor PCoIP sessions are not displayed as expected KB article" (1030566) from VMware. Monitor PCoIP … [Read more...]

Obtaining VMware Guest Disk Free Space for NFS Sizing

I am often asked about sizing storage vis-à-vis how much free space within a guest VMDK eats into the overall size of the volume.  The answer can be drastically whether we are dealing with thick-provisioned VMDK's on FC or iSCSI LUN's, or thin provisioned VMDK's on NFS volumes.  The amount of free space present in guest VMDK's also comes into effect when calculating the impact of dedupe on the volume.  Add in some flexible volumes on NetApp storage and the amount of provisioned storage in the design changes significantly. There are several methods of obtaining the amount of free space in a … [Read more...]