I need help understanding backup report results

[dpcallais]

Hello,

I've been doing some backup tests with Veeam v9 and I'm having trouble understanding the results.

For example, in one backup job I'm using the new file exclusions feature of Veeam v9 to backup only a specific directory containing 285 GB of SQL SAFE files. The backup reports shows the following information:

Data Read: 386.5 GB
Transferred: 276.5 GB
Backup Size: 276.9 GB
Dedupe: 7.9x
Compression: 1.4x

I don't understand why it shows 385.5 GB of data read when there was only 285 GB of data to backup and when I go to restore the data, it still only adds up to 285 GB. I have the settings set to exclude deleted file blocks and swap file blocks. Also, shouldn't the resulting backup file size be a lot smaller than just 276.9 GB based on the dedupe and compression rate that the report is showing?

Here is different example. In this backup job, I'm backing up the entire server without using the file exclusions feature. This server is mostly used as a file server and has 356.3 GB of used data on a hard disk with 546 GB total space. The backup report shows the following information:

Data Read: 376.2 GB
Transferred: 198.7 GB
Backup Size: 198.9 GB
Dedupe: 1.4x
Compression: 1.9x

This one is a bit less extreme, but still shows a Data Read number that is greater than the amount of data on the server. And I still don't understand how the reported dedupe and compression numbers results in a Backup Size of 198.9 GB. I've tried the formula 376.2 (data read) / 1.4 (dedupe) / 1.9 (compression) and that results in 141 GB but the Backup Size is 198.9 GB.

I appreciate any help in helping me understand these results. Thanks!

[Gostev]

I don't understand why it shows 385.5 GB of data read when there was only 285 GB of data to backup

Veeam does image-level backup, not file-level. Even if some file occupies only a part of a block, we still need to read and store the entire block.

And I still don't understand how the reported dedupe and compression numbers

Please open a support case to let us investigate, as these numbers look unexpected.