It’s time to start a script editor to write some Powershell code. So now we know the formula, the next step will be to find the data to fill the parameters to calculate the disk space requirements. So make sure to visit it once in a while.

There is a lot of good information there. This formula comes from the Veeam Communities. R = number of rollbacks (or increments) according to retention policy (14 by default)ĭ = average amount of VM disk changes between cycles in percent (we use 10% right now, but will change it to 5% in v5 based on feedback… reportedly for most VMs it is just 1-2%, but active Exchange and SQL can be up to 10-20% due to transaction logs activity – so 5% seems to be good average) This is the formula:ĭata = sum of processed VMs size (actually used, not provisioned)Ĭ = average compression/dedupe ratio (depends on too many factors, compression and dedupe can be very high, but we use 50% – worst case)į = number of full backups in retention policy (1, unless backup mode with periodic fulls is used) Before you can calculate these values you need to know the formula which Veeam uses to calculate the storage needs.

You can use the Check Space button to verify if there is enough space to write the backup to disk:īut is it possible to get this values via Powershell. When you edit or create a new backup job in Veeam Backup and Replication. This post is about how to calculate the storage needs for the configured Veeam Backup Jobs.

Backup calculator veeam