One of the popular use cases for using Zerto Virtual Replication is migrating workloads to the cloud with minimal downtime. This is possible due to two major advantages of using Zerto technology; continuous replication, which means the latest copy of the data is already in the cloud, and the efficiency of the live failover function, which means even a large group of VMs can be created and powered on in the recovery site within minutes.
Before we discuss the update process itself lets outline the role of VMware tools in our VMs. The importance of VMware tools cannot be overlooked, as they are effectively the drivers for your operating system running in a virtual machine. It’s not just about the graphics driver and the mouse/keyboard performance in the console as well. Whilst that is also the case, the biggest benefits are much more important, and relevant even to operating systems that don’t care for a GUI, i.e. *nix systems. The drivers included in VMware tools are, among others, the VMXNet network adapter drivers, which will provide your VM with 10Gb connectivity, and the Paravirtual SCSI driver, which will allow you to utilise the performance benefits of all-flash storage arrays, whilst keeping CPU utilisation low.
We will cover the alternative methods in the second post of this series. Be sure to check them out as they can be quite time saving.
Whilst you might be using time synchronisation with ESXi host in your environment it is advisable to consider switching to using a NTP server. Time synchronisation is especially important within Active Directory environments. The default setting for time difference tolerance is only 5 minutes. This means that should any of your servers go out of sync, above this threshold, the domain controllers would stop trusting them and not provide authentication services. This means that any applications relying on AD would effectively stop working. Within an AD environment, Microsoft recommends that the PDC of the root domain in the forest syncs it’s time with an external NTP server and the remaining domain controllers sync up to that PDC. More information on that can be found in this article. For any non-AD environments please consult the documentation of the application to establish what is the recommended time sync setting.
For optimal results in migrating workloads to a VMware based cloud with Zerto, its important to make sure the following points are addressed prior to moving your workloads to the cloud:
1. Make sure the virtual hardware version of your VMs is supported within the iland environment.
2. Check if VMware tools are up to date to ensure good performance of the VM.
3. Disable time synchronisation with the host and use an NTP server to ensure your VMs are always in sync.