Strange Issues With Microsoft Clustering and ESXi

I have some legacy applications that require Microsoft Clustering which are running on ESXi 6.0.  Using Microsoft Clustering on top of VMware does not give you many benefits.  Things like HA and moving workloads across nodes is already available using virtualization.  What clustering does do is create more places for things to break and give you downtime.  Really the only benefit I see with clustering in a virtualized environment is the ability to restart a server for system updates.

RDM’s are required for using Microsoft Clustering.  RDM “Raw Device Map” gives the VM control of the LUN such as it was directly connected to it. To set this up you need to add a second SCSI controller and set it to physical mode.  Each disk must then share the same SCSI controller settings for every VM in the cluster. The negative side to doing this is that you lose such features as snapshot and vmotion.  When using RDM’s with physical mode you should treat those VM’s as if they were physical hosts.

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The problem occurred when one of the clustered nodes was rebooted.  The node never came back online, and when checking the console it looked like the Windows OS was gone.  Powered off the VM and removed the mapped RDM’s.  When powering on the VM Windows booted up fine.  I Found that very strange so powered it off again and added the drives back.  That is when  I got the error invalid device backing.  VMware KB references the issue, and it basically says there is an issue with inconsistent LUN’s The only problem was I did have have consistent LUN’s.  I put in a ticket with GSS, and the first level support was not able to help.  They had to get a storage expert to help out. He quickly found this issue which was the LUN ID had changed. I am not sure how that occurred, but it was not anything I could change  When adding the drives in the VM’s the config it makes a mapping from the VM to the LUN.  When the LUN ID changed the mapping did not.  The only fix was to remove the RDM’s from all VM’s in that cluster and then add them back.

vCenter Fails after Time Zone Change

We recently changed our NTP server, and I needed to update all or hosts and vCenters.  I have a handy powershell script to update the ESXi hosts, but that script does not work on the vCenter servers.  I log into the server using port 5480 to gain access to the vCenter Management. I login as root and notice that the time zone is UTC.  I am in the Central time zone so I wanted to change it from UTC.  Turns out if you do that it break everything.  I had to learn this the hard way, and once I changed the time zone I was not able to log into vCenter.  I had to then go back and change the time zone back to UTC to regain access. Capture.

Only Default Printer Mapping Over With View 6.2

I recently had an issue with only the default printer being mapped over from the local Windows 7 PC to the View Client session.  It did not make any sense to me.  I had 10 printers mapped yet only 1 was showing up.  It turns out its a limitation of Windows 7.  If all the printers are using the same Driver and Port then you will only see the default printer under the Devices and Printers page.  If you right click that printer it will list all the printers you have mapped.  When you try to print something it will also list all your printers.

vCenter Server Resource Missing or Invalid

Recently I was trying to deploy an OVA file.  After selecting the storage I recieved the following error. capture

I tried downloading the OVA again, but still had the same issue.  Luckily it was an easy fix.  I was trying to deploy the OVA at the Cluster level.  What I needed to do was deploy the OVA at the ESXi level in vCenter.  Hopefully in a future vSphere update this will no longer be an issue.

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