Selecting a transport mode for VMware backups

To set the preferred transport order or hierarchy for backup or restore operations on VMware virtual machines, specify the vmvstortransport option.

Before you set the vmvstortransport option, review the following information:

• In most cases, set the vmvstortransport option to default (san:hotadd:nbdssl:nbd). If you do not specify a value for the vmvstortransport option, the default value is used.

  The optimal transport mode depends on the composition of the backup environment. Table 1 specifies the transport mode to use for specific backup environments.

  Table 1. Preferred transport modes for specific backup environments

  Backup environment	Value for the vmvstortransport option
  You want to offload backup traffic from the LAN, and instead, move it over a SAN.	san
  You are using a data mover node that is installed on a virtual machine to back up other virtual machines. The backups can be moved over a SAN or a LAN.	hotadd
  You are backing up virtual machines over an Ethernet LAN; you either do not have, or do not want to use, a SAN to offload backup traffic from the LAN.	nbd
  You are backing up virtual machines over an Ethernet LAN and you want to use SSL to encrypt the data. Note that encrypting data can degrade backup performance.	nbdssl

• The values that are listed in Table 1 are the preferred transport methods, but you might not want to specify a single transport method as the value. You might specify multiple transport methods so that you can fail over to another transport method when the first one fails; otherwise, the operation might fail. However, you might want to restrict this option so that only a certain set of transport methods is used. If you leave an entry out of the colon-separated value list, that entry is no longer available and is skipped.
• Consider the effects of the setting on performance.

  It is typically preferable to use the fastest available transport mode. However, in some environments, it might be necessary to avoid certain transport modes or emphasize others for resource management purposes.

• Consider the potential trade-offs for this setting.

  Specifying a slower transport mode might reduce the aggregate throughput of the backup environment.