Backup jobs using Virtual Appliance (HotAdd) transport mode take longer after installing 9.5 Update 3a

After installing Veeam Backup & Replication 9.5 Update 3a, the backup duration may be significantly increased for jobs using the Virtual Appliance (HodAdd) transport mode. Other transport modes (NBD/NBDSSL, Direct SAN, Direct NFS) are not affected.

This is a known issue affecting VMware VDDK (Virtual Disk Development Kit) versions 6.5.2, 6.5.3 and 6.7. Please refer to VMware KB55418 article for more information.

A hotfix for Veeam Backup & Replication 9.5 Update 3a (build 9.5.0.1922) is available to switch to using unaffected VDDK versions. To install the hotfix:

1. Stop all Veeam jobs and Veeam services
2. Copy these files and folders to an alternate location from the backup server and all backup proxies to have a backup:

   C:\Program Files (x86)\Veeam\Backup Transport\x64\vddk_6_5
   C:\Program Files (x86)\Veeam\Backup Transport\x64\vddk_6_7
   C:\Program Files (x86)\Veeam\Backup Transport\x64\VeeamAgent.exe

3. Replace the files on the backup server and all backup proxies listed in the previous step with those found in the hotfix package
4. Start all Veeam services

Note: If after applying the hotfix HotAdd transport mode stops working entirely, install Visual C++ Redistributable Packages for Visual Studio 2013 package on the backup server and all backup proxies.

Download the hotfix