Very slow backup, even using separate network.

[ivanildogalvao]

I'm dealing with a problem with slow backups, using Veeam 8.0 U3, installed on a physical Dell server, with Windows Server 2016, 32GB RAM. The vCenter Server is also installed on this same server, ie the server is vCenter and Veeam at the same time.
It has two 1Gb network cards, one connected to the LAN and the other connected to the SAN. On the Veeam console, I added vCenter with its IP of the SAN, although it also has an IP on the LAN. ESXi hosts also have a vmk interface on the SAN network, portgroup with the "Management" option, so the idea is to force backup traffic to pass through this network and never over the LAN.
In VMware Backup Proxy, I created a traffic rule, to force Veeam to use only the SAN network to transfer files.
But it is not working, the backup always happens over the LAN and it is extremely slow to the point where the backup of 10 simple VMS takes more than 20 hours.
When the backup is going on, I see heavy traffic on the Veeam / vCenter LAN interface and nothing on the SAN network interface.
The storage is a Dell, iSCSI.
Does anyone have any idea what still needs to be done for backup traffic to pass exclusively over the SAN?

Thanks !

[Gostev]

Hello,

You cannot force the Network transport mode to a particular network, as this is not something VMware supported until recently.

To perform backups over SAN network, you need to use the Direct SAN transport mode. For this mode to work, you must present your VMFS volumes to your backup proxy server (see the sticky FAQ topic for more information). If you run into any difficulties, please do feel free to open a support case, and one of our engineers will help you over a live session.

Thanks!

[ivanildogalvao]

There is no way to consult Veeam, as the customer in question has not renewed the support.
Searching, I saw some articles that show how to configure Veeam to access datastores in the Vmware cluster (direct san access).
But I confess that I don't feel very much like trying this configuration, I'm afraid to compromise the datastore and the VMware hosts become unable to access it.

[Gostev]

This might have been an issue 10+ years ago, but for along time now we protect against this by automatically disabling Windows auto-mount functionality on our backup proxy servers. Of course, in the end it is up to you - but we estimate that the Direct SAN transport mode is used as the primary transport mode in about 200K of unique Veeam Backup & Replication installations at this time.

[ivanildogalvao]

Ok, I will do a lab simulation first, to understand the operation correctly.
Then I apply it in the production environment.

Thanks for the clarifications!