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Date: 8/20/2018

Field Technical Notice: FTN-20180628

ZVR Versions Affected: 5.0, 5.5 and 6.0

Description

Reinitializing or restoring a vCenter database can lead to a mismatch between the vCenter database and Zerto Virtual Replication.  The mismatch situation can affect the ZVR management of a VM or other objects managed by vCenter.   Zerto recommends running the VCenter Inspection Tool to check if vCenter database management operations such as reinitializing or restoring a vCenter database have taken place after the ZVR has been installed.

Background

Any vCenter database maintenance operations such as reinitializing, rebuilding, recreating or restoring the vCenter database may cause the internal vCenter entity IDs (known as MoRef) to be reset. Restoring the vCenter database from a backup or from a snapshot can also potentially cause the MoRef to be reset.
 
ZVR versions 4.5 and below could not handle such a situation, and ZVR would need to be re-installed (as described in this KB article). As of version 5.0, ZVR can continue to operate after such a maintenance operation. Zerto has recently realized that after a while, a potentially dangerous situation can occur in the customer’s environment after such vCenter database maintenance operations.
 
 ZVR sites can be in one of the following conditions:

1. Normal environment in which no vCenter database maintenance operations have taken place since ZVR was installed
2. vCenter database maintenance operations have taken place and there can be a mismatch between vCenter and ZVR

Zerto has released a verification tool called the VCenter Inspection Tool.  This tool determines if there has been vCenter database maintenance operation on the vCenter database after ZVR was installed.  If there have been vCenter database maintenance operations after ZVR installation then there is a possible mismatch between the vCenter database and ZVR.  If there is a mismatch between vCenter and the ZVR, then there is a risk of operational problems.
 
Additionally, Zerto has released an update to ZVR which prevents mismatches between the ZVR database and the vCenter database.  ZVR 5.5U4 Patch 2 and ZVR 6.0U3 and subsequent releases prevent this type of mismatch.

Actions to take

Zerto recommends that you upgrade to ZVR 6.0U3 or subsequent release to prevent any mismatches between the ZVR database and the vCenter database.

Additionally, Zerto recommends that you run the VCenter Inspection Tool on each site to detect if there have been vCenter database maintenance operations.  Please reference this Field Technical Notice number when contacting Zerto Support.
 
The verification tool assesses the state of the vCenter and ZVR databases.  The actions to take for each condition are:

1. Normal environment – no further action required
2. vCenter database maintenance operation has taken place after installation of the ZVR – Zerto recommends that you contact Zerto support and reference this Field Technical Notice number to assist in resolving any potential database mismatch between vCenter and ZVR

See Also

Reinitializing the vCenter Server database (external link to VMware’s KB)
ZVR 4.5 Recovery after Recreating the vCenter database KB article
Verification tool – Please go to MyZerto -> Support -> Downloads on the Tools tab to download the VCenter Inspection Tool.