Troubleshoot Unable to Use-Hot Add with Linux proxy after Veeam v12 upgrade

  • 25 September 2023

Userlevel 7
Badge +7

Hello everyone,

I would like to draw your attention to an issue detected following the Veeam upgrade to version 12 at one of my clients. This also applies to new installations.

During backup and restoration operational tests, which are crucial to perform during installation/post-upgrade, the following error message appeared when restoring a VM: Unable to use Hot-Add mode.

While analyzing the logs of a backup job, the proxies switched from Hot-Add to NBD mode.

After analyzing the logs and isolating the issue to a single proxy (Forcing the proxy to use only Hot-Add + creating a test backup job with only this proxy), I was able to obtain a more informative message.

There is a Veeam Knowledge Base article available at

To resolve the error, it is necessary to disable "multipath" on the Linux proxies, following the procedure outlined in the KB. After applying the fix, backups and restores successfully utilize the Hot-Add mode, resulting in improved performance.

I apologize for the screen quality, I had a low resolution when capturing them.

Have a great day.


Userlevel 7
Badge +19

I’m getting ready to create new Linux proxies myself. A couple virtual for hotadd, and a couple physical for BfSS. Makes sense not to have multipath enabled on a virtual Proxy as it’s only used for hotadd. Weird it comes up with that error though. 

Thanks for the share @Stabz .

Userlevel 7
Badge +9

thx for share m8 👍

Userlevel 7
Badge +21

Thanks for sharing this.  I am going to check our Linux Proxies to ensure multipath is disabled. 

Userlevel 7
Badge +6

Thanks for the share.  I plan on creating my first linux proxies in the next couple weeks and haven’t come across this yet.

Userlevel 7
Badge +8

Looking into linux proxies on my rebuild as well. happy to see this so I won’t panic if it happens :) 

Userlevel 7
Badge +22

Great info. Not using hot add because of NFS.. and you know what happens when you try and use hot add on NFS :).. reminds me of watching Star Trek when they set their phasers to STUN :)