Just a short note to explain why those of you who have been following me may be curious as to why I suddenly disappeared from EE all of a sudden and apparently started ignoring all of your messages for the last couple of months.
Without going into too much detail, I've basically been in and out of hospital with a rather serious condition. My last stint in hospital was 4 1/2 weeks and I'm finally now home again on a "Hospital in the Home" program where district nurses regularly visit my home and I go back into the hospital once a week for doctors reviews.
The situation I'm in isn't about to change real soon, but I'm confident I'll beat it eventually :-)
So that's my story gang.. My apologies for the lack of replies and if I do seem to disappear, please know it has nothing to do with Experts Exchange forums, which I continue to thoroughly enjoy.
I'm going to start something new at EE, Tips from the VMware vSphere Datacentre... real world tips, that get you through that tricky moment, when all things are turning to that brown stuff.... This happened to me today, adding 5 new vSphere ESXi hosts to a Cluster of 150.
Andy's VMware vSphere tip#1 - HA Operation Timeout - A Host or Hosts refuse to bring HA (High Avaibility online), after upgrading vCenter Server, or adding new hosts to vCenter Server datacentre, no matter what you try, you obtain an Operation Time Out, you look at the FDM.log as advised here - https://kb.vmware.com/s/article/2011974.
Solution. - Just Edit Cluster Settings - and Disable and Re-enable vSphere HA.
Simples! All that work browsing logs and Reconfigure HA for the Host not required. This does not affect any VMs, and HA will just be unavailable for 30 seconds why you turn on and off.
If you need to discuss this, please post a question to the VMware topic area.
Andy's VMware vSphere tip#3 - Experiments in TIME. Just call me a TIME LORD!
Real life example, a client added 20 new hosts to a large vSphere Cluster, DRS was enabled, and after a few minutes, VMs started to populate the new hosts. (via VMotion/DRS)
A very large outsourcer, then suddenly found issues with Active Directory Replication across the business and also Microsoft Exchange email servers services started to fail.
Because of TIME, TIME had skewed between Active Directory servers and Microsoft Exchange servers by 1.5 hours! and all stopped replicating, and services failed! Active Directory and Microsoft Exchange failed. Logons and email stopped working for many thousands of employees!
The reason, a few of the new ESXi hosts, were syncing time from a rouge time server, which was giving the WRONG time, the time in fact was 1.5 hours ahead.
You may be thinking, ah, they are using VMware Tools to sync to host! - No!
This function has been removed from VMware Tools for many years!
BUT here is a golden nugget, did you know that a vMotion of a VM will sync time with the host unless disabled!
Time is resynchronized when you migrate the virtual machine using vMotion, take a snapshot, restore to a snapshot, shrink the virtual disk, or restart the VMware Tools service in the virtual machine (including rebooting the virtual machine).
Andy's VMware vSphere tip#2- When creating a virtual disk for VMware vSphere (or Hyper-V), always start small, and expand later. It's much easier to expand a virtual disk, than reduce a virtual disk. Do not be tempted to create 1 TB virtual disk, you will find it difficult to reduce the size. If you have made this mistake you can refer to my EE Articles.