Hi ​@hs08 -

These items get explained pretty well in a Forums post by Ryan Jacksland (former Veeam Vanguard). See below:

https://forums.veeam.com/veeam-agent-for-windows-f33/how-to-read-the-backup-result-t28657.html

The next comment, from Veeam Product Manager Mike Ressler, confirms his explanation.

Best.

Processed is the total size of the disks being backed up, read is the actual data being read off the disks (which excludes empty or unchanged blocks), and transferred is the size of the data being sent to the repository after compression and deduplication. 

See here for more information. 

We have a link in our User Guide that explain this: https://helpcenter.veeam.com/docs/backup/vsphere/realtime_statistics.html?ver=120#statistics-counters

Basically:

 

• Processed — total size of all VM disks processed by the job.
• Read — the amount of data read from the datastore by the source-side Data Mover prior to applying compression and deduplication. For incremental job runs, the value of this counter is typically lower than the value of the Processed counter. Veeam Backup & Replication reads only data blocks that have changed since the last job session, processes and copies these data blocks to the target.
• Transferred — the amount of data transferred from the source-side Veeam Data Mover to the target-side Veeam Data Mover after applying compression and deduplication. This counter does not directly indicate the size of the resulting files. Depending on the backup infrastructure and job settings, Veeam Backup & Replication can perform additional activities with data: deduplicate data, decompress data prior to writing the file to disk, and so on. The activities can impact the size of the resulting file.