vSAN backup error :Unable to hot add source disk

[MatYXL]

Veeam Case #07601162

Dear team, I would like to ask for assistance
Currently, our company has two vSAN clusters: Cluster1 and Cluster2. Backing up VMs in Cluster2 using Veeam fails, while the same VMs can be successfully backed up when moved to Cluster1. The VMs in Cluster1 back up normally, but when I migrate them back to Cluster2, the backup fails again .As long as the VM is in Cluster2, the backup fails. I have configured proxies on each host in Cluster2, but the issue persists. Thanks in advance.

#VMware ESXi, 7.0.3 #Veeam12.3

The backup logs and error codes are as follows:

Code: Select all

PM 02:24:55	Queued for processing at 2025/2/12 PM 02:24:55 	
PM 02:24:55	Required backup infrastructure resources have been assigned 	00:00
PM 02:25:01	Processing VM01 Error: Failed to open VDDK disk [[vsanDatastore (XXXXXXXXX)] 0c477767-bab5-9043-c380-b496913a49ee/VM01.vmdk] ( is read-only mode - [true] ) Logon attempt with parameters [VC/ESX: [S3vcsa01.WWWWWW.com];Port: 443;Login: [veeambak];VMX Spec: [moref=vm-12241];Snapshot mor: [snapshot-14087];Transports: [nbd];Read Only: [true]] failed because of the following errors: Failed to open disk for read. Failed to upload disk 'vddkConnSpec>' Agent failed to process method {DataTransfer.SyncDisk}.  	06:42
PM 02:25:01	VM processing started at 2025/2/12 PM 02:25:01 	
PM 02:25:01	VM size: 100 GB 	
PM 02:25:02	Resetting CBT per job settings for active fulls 	00:06
PM 02:25:09	Getting VM info from vSphere 	00:12
PM 02:25:22	Creating VM snapshot 	00:02
PM 02:25:29	Saving [vsanDatastore (XXXXXXXXX)] 0c477767-bab5-9043-c380-b496913a49ee/VM01.vmx 	00:00
PM 02:25:29	Saving [vsanDatastore (XXXXXXXXX)] 0c477767-bab5-9043-c380-b496913a49ee/VM01.vmxf 	00:00
PM 02:25:30	Saving [vsanDatastore (XXXXXXXXX)] 0c477767-bab5-9043-c380-b496913a49ee/VM01.nvram 	00:00
PM 02:25:30	Using backup proxy 10.79.99.31 for disk Hard disk 1 [hotadd] 	02:58
PM 02:28:29	Unable to hot add source disk VM01.vmdk, failing over to network mode... 	
PM 02:28:30	Hard disk 1 (0 B) 0 B read at 0 KB/s [CBT]	02:57
PM 02:31:34	Removing VM snapshot 	00:03
PM 02:31:43	Error: Failed to open VDDK disk [[vsanDatastore (XXXXXXXXX)] 0c477767-bab5-9043-c380-b496913a49ee/VM01.vmdk] ( is read-only mode - [true] ) Logon attempt with parameters [VC/ESX: [S3vcsa01.WWWWWW.com];Port: 443;Login: [veeambak];VMX Spec: [moref=vm-12241];Snapshot mor: [snapshot-14087];Transports: [nbd];Read Only: [true]] failed because of the following errors: Failed to open disk for read. Failed to upload disk 'vddkConnSpec>' Agent failed to process method {DataTransfer.SyncDisk}.  	
PM 02:31:45	Processing finished with errors at 2025/2/12 PM 02:31:45

[david.domask]

Hi MatYXL, welcome to the forums.

Thank you for sharing the case number and sorry to hear about the challenges.

I see the case was opened as a "Free" case (Community Edition), and such cases are supported on a "Best-Effort" basis. If you have an active support contract, please install it to your server and upload a fresh set of logs to the case and use the Talk to a Manager button and request the case be converted to a paid Support case. The license must be installed on the server prior to log export for Support to confirm the valid license.

We won't be able to troubleshoot the hot-add issues over the forums, but I would advise checking the Requirements and limitations for hotadd. The logs above unfortunately are unclear, but looks like the proxy was not able to hotadd the disks for some reason and tried to connect via NBD, but that also failed, so my guess would be that the proxy can't reach one (or more) of the ESXi hosts, but this is just a guess.

Please install a valid license with an active support contract and continue with Support as advised. Thanks!

[MatYXL]

Thank you for your response. We are currently encountering this issue during the POC testing phase. Until this problem is resolved, we are unable to determine the usability and effectiveness of this product, as well as assess the compression ratio and compatibility with our company’s environment. This makes it difficult for me to report the testing results to my manager. Since the CE version case is on a best-effort basis, I am seeking assistance here. Thank you.

[david.domask]

Hi MatYXL,

Evaluation Licenses are eligible for Support, and I'm afraid a Support case is required here as noted when creating a topic. The forums are not a Support Forum, and we won't be able to troubleshoot over the forums.

I would advise check as suggested before, but further analysis will require a Support case.

[MatYXL]

Thank you for your response. I understand now that there is an evaluation license available. We will inquire with the SI regarding the evaluation license. Thank you once again.