How to Check Negotiated Speed on Fibre Channel HBAs

Fibre channel storage is great because it mostly “just works”. You provision storage, assign it to the WWPNs, rescan the adapters, and the luns are presented. There isn’t a lot of configuration in the GUI and, honestly, it can be hard to detect link speed or even if a link is up. In the Storage Adapter tab you can see if a path is down, but how do you detect the link speed?

Check and Configure Time Service Datacenter-wide

I once had an opportunity to improve and standardize ESXi host time synchronization in an environment with hundreds of hosts. There had been issues with time sync and drift that needed to be addressed. To fix this I turned to PowerCLI to do a quick and dirty dump of the configuredNTP settings on each of the hosts in the Datacenter. Get-VMHost | Get-VMHostService |Where-Object {$_.key -eq "ntpd"} This commandlet returns output which gets us part of the way to the solution, but we can refine it and make it better.

Investigating VM Configuration Changes

Tracking resource configuration is a common struggle for an enterprise level environment. Even SMBs can have trouble keeping track of how their memory is provisioned and when it changes. What’s worse, VMware’s vSphere Client doesn’t provide any insight as to what changes when someone edits the virtual machine settings. An event named”Reconfigure virtual machine” hits the task log but this isn’t a lot of information. If you open Edit Settings and click OK vCenter registers this event even if you didn’t change anything.

Detecting a Misconfigured vSwitch

Years ago I received a call for help from someone setting up a vSphere host. The install had never worked right and the clients were upset at the upgrade. It sometimes took 30 seconds to connect to a server and their SQL applications would crash daily. My intuition told me there was something strange going on with the network. It was a very basic install with one Standard vSwitch doing management and virtual machine network traffic.

Disable Atomic Test and Set for Incompatible Storage Arrays

After performing an upgrade from ESXi 4.1/ESXi 5.0 to ESXi 5.5 u2 I noticed increased latency events on hosts. More troubling, the affected hosts were frequently dropping all presented datastores, though they would reconnect within a few seconds. The events may appear in your event log as below: While there are many possible causes to explore these sorts of connectivity issues, one that is often overlooked is how ESXi heartbeating to the datastores.