Initial continuous export job completes successfully; however subsequent applications of delta to the virtual standby system fail at the end of the export process when consolidation of the snapshots should happen. The error displayed is the following:
Exception chain: Task 'Create virtual machine snapshot' failed: An error occurred while taking a snapshot: The parent virtual disk has been modified since the child was created. The content ID of the parent virtual disk does not match the corresponding parent content ID in the child. For more details open events on ESXi host/vCenter Creating the virtual machine snapshot 'MM/DD/YYYY HH:MM:SS' for the virtual machine '[VM Name]' has failed.
From vCenter, the virtual standby system is available, but the snapshot VMDKs are listed with 0MB and cannot be used.
This error is caused by a Content ID (CID) mismatch within the snapshot chain of the virtual standby VM.
Each virtual disk (.vmdk) and its snapshots have a CID. A snapshot (child disk) keeps a record of its parent disk's CID to maintain integrity. If the parent disk is modified for any reason, its own CID changes, breaking the chain.
In a virtual standby process, this can be triggered by:
Network interruptions during data replication.
Storage latency on the destination datastore.
Errors in the replication or consolidation process that inadvertently modify a parent disk in the snapshot chain.
Because the standby process repeatedly creates and consolidates snapshots, it is more susceptible to these kinds of interruptions.
VMware has addressed this Issue in the following article:
To resolve this issue, you must manually correct the broken CID link in the snapshot chain of the standby virtual machine.
⚠️ Important: These steps must be performed on the destination ESXi host where the failed standby VM resides. Do not modify the source/production VM.
Connect to the ESXi Host Use SSH to log into the ESXi host that is running the virtual standby VM. If you are using Windows PowerShell or another command-line terminal, you can use the ssh command.
Open PowerShell and type the following command, replacing username and ipaddress with your host's credentials and IP address:
ssh root@192.168.1.100
Accept the fingerprint: The first time you connect, you will be asked to verify the host's authenticity. Type yes and press Enter.
The authenticity of host '192.168.1.100 (192.168.1.100)' can't be established.
ECDSA key fingerprint is SHA256:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Enter the password: You will then be prompted to enter the password for the user account.
Navigate to the Standby VM Directory
Browse to the datastore and directory containing the files for your standby VM. For example:
cd /vmfs/volumes/datastore_name/standby_vm_name/
Identify and Correct the CID Mismatch
You will now need to inspect the descriptor .vmdk files to find and fix the break in the chain.
Follow the detailed command-line instructions provided in the Broadcom Knowledge Base article: "The parent virtual disk has been modified since the child was created" error.
The process involves:
Using a text editor like vi to open the descriptor file of each snapshot (e.g., standby_vm_name-000001.vmdk).
Comparing the parentCID value in the child snapshot with the CID value of its parent disk.
Editing the incorrect parentCID in the child's descriptor file to match the actual CID of the parent disk, restoring the link.
Retry
Once the CID has been corrected, rerun your virtual standby job to confirm the issue is resolved.