As we discussed here earlier, there are 3 transport modes to get data from vSphere for backup.
These modes are also available for restore. By default, first mode (order: SAN, Hotadd, NBD) that meet requirements, is selected for restore. For SAN direct mode, a requirement is thick provisioned disk type. You can select each available type (thin, thick eager and lazy zeroed) in restore wizard.
My recommendation: If you want to leverage SAN direct mode, choose Thick eager zeroed! This option is much faster than lazy zeroed!
I tested these settings in different environments. For example, I saw differences of
- 67 % (150MB/sec for eager vs. 100MB/sec for lazy),
- 93 % (226MB/sec for eager vs. 16MB/sec for lazy).
See here different wizards
- VM restore
- VM Disk restore
- In documentation of version 9.0, you see a hint, for lazy zeroed, vCenter is needed for zeroing.
Since v9.5 no difference is made anymore between lazy and eager zeroed.
See here one of the threads about SAN direct restore performance in Veeam forum.