Can anyone here please suggest me what do I need to do as pre cautions and mitigation plan when applying Windows Update to the following servers:
1. Windows Server 2008 R2 VM - Primary DNS servers (Production Data Center) , Domain Controller / Global Catalog Server (Schema Master) - (220 Updates to be applied)
2. Windows Server 2008 R2 VM - Secondary DNS servers (Production Data Center) , Domain Controller / Global Catalog Server (Domain naming master) - (215 Updates to be applied)
3. Windows Server 2012 R2 Physical box - Primary DNS & DHCP servers (HQ Office) , Domain Controller / Global Catalog Server (RID & Infrastructure master, PDC Emulator) - (110 Updates to be applied)
For the VM in number #1 and #2 does updating the WIndows during the working hours can have some impact in the Name resolution and Exchange email flow ? Can I take snapshot on both VMs at the same time and roll it back when it failed or hangs when applying some updates ?
For the physical server in #3, how can I prevent any outage during the working hours patching ?
Sometimes when I apply the updates to the WIndows Servers, there are some things that caused the updates to be failed thus taking too long not responding back to remote desktop.
Any help would be greatly appreciated.