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What is the difference between Veeam Backup & Replication and Veeam Backup Agent?

Very simply put: VBR is good for backing up virtual machines running on hypervisors, VBA is good for backing up stand-alone servers or workstations which are not virtualized.

How do I back up my hypervisors (the host machines)?

It is not recommended to back up hypervisors. A senior engineer of Veeam explains it this way:

It's a bad idea to backup the entire host with all VMs.

The best practice is:

1. Don't worry about backing up the host itself, as redeploying one takes little time (comparable with performing the restore). But if you do still want to back the host up, then use Veeam Agent for Windows excluding the volume that hosts your VMs.

2. Backup your VMs with the specialized VM backup product, such as Veeam Backup & Replication. 

In terms of retention: what is the difference between days vs. restore points?


Days mean: keep restore points created during the last X days (and you give X as the number of days).

Restore points mean: keep X restore points regardless of how old they are.

E.g. Settings: keep restore points for 7 days, and the backup runs 2x a day --> in 7 days 14 restore points are created and retained. On the 8th day, 2 restore points (the two oldest) will be deleted after the 2 newest are created.

E.g. 2. Settings: keep 7 restore points, and the backup runs 2x a day --> 7 restore points are created within 3,5 days. When the 8th restore point is created, Veeam then goes on and deletes the oldest restore point.

What do the different options under storage optimization mean when I create a backup job?


To utilize the capabilities of a given storage device as good as possible, Veeam provides 4 different options depending on the backup size and location.

Storage optimization option

Block size


Local target (large blocks)

4096 KB

Recommended for files that are larger than 16 TB.

This option will provide the lowest deduplication ratio and the largest size of incremental files.

Local target

1024 KB

Recommended for backup and replication to SAN, DAS or local storage.

This option provides the fastest job performance but reduces the deduplication ratio, because with larger data blocks it is less likely to find identical blocks.

LAN target

512 KB

Recommended for backup and replication to NAS, and onsite backup and replication.

This option provides a better deduplication ratio and reduces the size of a file because of reduced data block sizes.

WAN target

256 KB

Recommended if you are planning to use WAN for offsite backup and replication.

This option provides the maximum deduplication ratio and the smallest size of files that allows you to reduce the amount of traffic over WAN. 

When should I use a backup window and when network throttling?


If you set up a backup window, you tell Veeam to abort the job when the backup window (the time frame while the job can run) is over. If your backup window is from 7 PM to 7 AM but the backup is not yet finished in the morning, Veeam will "pause" the job at 7 AM and continue at 7 PM.

Backup windows are recommended if there's a time slot (e.g. during the day) when the given server(s) is under a heavy work load, and all the available resources must be spared for production activities, and none can be spared for backups.


If you set up network throttling, you tell Veeam to use only a small part of the available bandwidth. E.g. if you have 100 Mbps available and you set up network throttling to use only 50, Veeam will not increase the speed above that.

Network throttling is recommended if during production hours, the server has enough resources to run the backups but you'd like to avoid Veeam to use up all the available bandwidth.

With a backup window, you spare ALL the available resources, with a network throttling rule, you spare bandwidth.

What is the difference between the compression rates used by a backup job?


None compression level is recommended if you plan to store backup files and VM replica files on storage devices that support hardware compression and deduplication.

Dedupe-friendly is an optimized compression level for very low CPU usage. You can select this compression level if you want to decrease the load on the backup proxy.

Optimal is the recommended compression level. It provides the best ratio between size of the file and time of the procedure.

High compression level provides additional 10% compression ratio over the Optimal level at the cost of about 10x higher CPU usage.

Extreme compression provides the smallest size of the file but reduces the performance. It provides an additional 3% ratio over High at the cost of 2x CPU usage. 

What is GFS backup?

GFS stands for "Grandfather-Father-Son". This type of backup uses a different retention period compared to the one set up in the job. You can define a retention for weekly, monthly and yearly backups, meaning that e.g. the restore point created on the 1st of a month will be kept for a month (won't be deleted, if the job retention is 7 days, and the restore point is older than that).

Important: GFS does not work with rotated drives. (Backups to USB devices.)


Veeam Backup for M365: how many licenses are consumed if one M365 mailbox is included in multiple VBM365 jobs?

Only one. Only new workloads (e.g. mailboxes, SP sites, etc.) consume additional licenses. (source: Veeam vendor support, Licensing Team)



What is WAN acceleration?


When is it recommended to use WAN acceleration?


What are the different backup types that I can set?


How many concurrent jobs / threads should be run on a Veeam server?