1-800-691-1991 | 9am - 8pm ET

Slow restore performance in SAN mode


In some cases, depending on infrastructure setup you can observe poor processing rate when performing full VM restore in SAN mode. You can notice as well that Network mode is faster.


If you restore Thick Lazy Zero disk using SAN mode, overall restore performance can be affected because of round trips through the disk manager APIs, AllocateBlock and ClearLazyZero requests. The reason that NBD mode can work faster in comparison to SAN mode (when not using block-sized writes) is because the write is performed by the host which has inside knowledge about layout of the vmdk. This inside knowledge must be requested from the host when VDDK is doing direct writes to the LUN.


Use alternative transport mode: network, virtual appliance
You can also try to restore in SAN mode via standalone ESXi. In some cases you may see a higher processing rate

More information at
Veeam Backup & Replication
Last Modified:
Please rate how helpful this article was to you:
5 out of 5 based on 1 ratings
Thank you for helping us improve!
An error occurred during voting. Please try again later.

Couldn't find what you were looking for?

Below you can submit an idea for a new knowledge base article.
Report a typo on this page:

Please select a spelling error or a typo on this page with your mouse and press CTRL + Enter to report this mistake to us. Thank you!

Spelling error in text

Knowledge base content request
By submitting, you agree that your personal data will be managed by Veeam in accordance with the Privacy Policy.

ty icon

Thank you!

We have received your request and our team will reach out to you shortly.


error icon

Oops! Something went wrong.

Please go back try again later.