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Best Practices for Veeam Backup & Replication 7.0 for VMware

Veeam Management Pack Help Center  > Best Practices for Deployment & Configuration >  Understanding Veeam Backup & Replication Options > How It Works: Transport Modes > Virtual Appliance

Virtual Appliance

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The Virtual Appliance mode utilizes the SCSI hot-add capability of ESX to attach disks of a backed up VM to the backup proxy VM or to the helper VM (depending on vCenter version you are using).


In this mode, VM data is retrieved directly from storage through the ESX I/O stack, instead of going through the network stack, which improves performance. Consider, however, that performing the hot-add of the source and target VM disks to the appropriate proxies requires a lot of communications with vCenter and from vCenter to the hosts. This step the would normally take 30-60 seconds. If you are sending data over a slow link, or if the change rate of the VM is low then you might find that forcing Network mode will give you better performance.


The Virtual Appliance mode is recommended and can only be used if the backup proxy is deployed on a VM running on ESX(i) host.

Please note that the ESX(i) host on which the backup proxy VM resides must have access to the storage where disks of a backed up VM are located. Also, consider that in this mode, parallel processing will process all the disks that it is able to but this will be limited to only 1 disk per proxy at a time. Thus, in the Virtual Appliance mode Veeam will be unable to process multiple disks on the same proxy. To support parallel multi-processing, you need to deploy multiple proxy VMs (see also


The Virtual Appliance mode does not support SATA disks. This is by design of VMware hot add functionality, which requires SCSI adaptors.

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