Question:

How can I avoid duplicate volume serial numbers on multiple servers created from a VMware template?

I am using a VMware template to create new servers, but I noticed that they all have the same volume serial number on the C: drive. This is causing replication issues and DFSR errors (error 9226) on the domain controllers. I tried to run sysprep manually on the new servers, but it did not change the volume serial number. Is this a normal behavior or am I missing something? How can I ensure that each server has a unique volume serial number?

Answer:

If you are using a VMware template to create new servers, you may encounter a problem with duplicate volume serial numbers on the C: drive. This can cause replication issues and DFSR errors (error 9226) on the domain controllers, as well as other potential conflicts with software activations or licensing. In this article, we will explain why this happens and how to prevent it.

Why do duplicate volume serial numbers occur?

A volume serial number is a unique identifier assigned to a disk partition by the operating system. It is different from the disk serial number, which is a physical attribute of the disk itself. The volume serial number is stored in the boot sector of the partition and can be changed by software tools.

When you create a VMware template from an existing virtual machine, the template inherits the volume serial number of the source disk. If you use this template to deploy multiple virtual machines, they will all have the same volume serial number on the C: drive. This is because the template does not run sysprep, which is a tool that prepares a Windows system for cloning and customization. Sysprep is supposed to change the volume serial number, among other things, to make each clone unique.

However, even if you run sysprep manually on the new virtual machines, you may find that the volume serial number does not change. This is because sysprep does not always change the volume serial number, depending on the version of Windows and the type of disk controller. For example, sysprep does not change the volume serial number on Windows Server 2008 R2 or later if the disk controller is SCSI. This is a known issue that has not been fixed by Microsoft.

How to avoid duplicate volume serial numbers?

There are several ways to avoid duplicate volume serial numbers on multiple servers created from a VMware template. Here are some possible solutions:

• Use a different disk controller type for the template. If you are using SCSI, try changing it to IDE or SATA. This may allow sysprep to change the volume serial number. However, this may also require reinstalling the operating system or the VMware tools on the template.
• Use a different partitioning scheme for the template. If you are using MBR, try changing it to GPT. This may also allow sysprep to change the volume serial number. However, this may also require converting the disk type or reinstalling the operating system on the template.
• Use a different disk format for the template. If you are using thick provisioning, try changing it to thin provisioning. This may create a new volume serial number for each clone. However, this may also affect the performance or the disk space of the virtual machines.
• Use a different cloning method for the template. If you are using vSphere, try using VMware Workstation or vice versa. This may also create a new volume serial number for each clone. However, this may also require exporting and importing the template or the virtual machines.
• Use a third-party tool to change the volume serial number manually on each clone. There are some free or paid tools that can change the volume serial number of a disk partition, such as VolumeID or Hard Disk Serial Number Changer. However, this may also require rebooting the virtual machines or reactivating the Windows license.

Conclusion

Duplicate

volume serial numbers on multiple servers created from a VMware template can cause replication issues and DFSR errors on the domain controllers, as well as other potential conflicts with software activations or licensing. To avoid this problem, you can try one of the solutions mentioned above, or contact VMware or Microsoft support for further assistance.