Impacts of re-installing vCenter on vSphere Replication and SRM 5.x/6.x.

Generally vCenter servers can crash for several reasons, But majorly when you have multiple products like SRM, VR & NSX registered to the vCenter it is kind of a challenge to get them functioning when  re-installation of vCenter occurs.

In this article we will majorly talk about SRM and VR as I hold my expertise in these products. Let me give you a technical overview on the reason behind the failure.

During vCenter 5.5 SRM/VR used to register with the vCenter with its FQDN or IP address due to which even though vCenter was re-installed, performing a modify of the SRM installer used to re-register with vCenter successfully and SRM used to function normally as expected.

With the introduction of 6.0 when PSC was involved in place of SSO, registration process was changed from vCenter’s FQDN/IP to vCenter’s instance id or UUID to be more precise.

This UUID can be found in the below mentioned path.

vCenter Appliance:

/etc/vmware-vpx/instance.cfg

Windows vCenter:

C:\programdata\VMware\vCenterserver\cfg\vmware-vpx\instance.cfg

So during registration process it would verify the respective vCenter with its UUID and store it in its concerned database rather than storing with FQDN/IP Address.

Hence whenever a vCenter was re-installed either from scratch or existing database it would generate a new UUID and SRM/VR would fail to identify the vCenter as database has already recorded the previous UUID and it would not consider the new UUID as multiple tables includes the original UUID entry which certainly has dependency with each other.

Updating the table manually is a tedious job as these entries are scattered across multiple tables. In certain cases it has yet failed to start the service due to complex architecture of the SRM database.

So we have two alternates to get past this issue.

• Restore a VM level backup of the vCenter which would retain its original UUID
• Reinstall SRM/VR with a new database and reconfigure it from scratch.

I would always recommend you to re-consider re-installing vCenter if you have multiple products registered.

I hope this article was informative. Watch out for more.