For upgrade...it's usually around 35-40GB. I will be doing one of my VBRs today and can let you know. 

It’s not exactly an upgrade. It’s simply a patch. Let me know versions of your upgrade please and i wil compare. Thanks.

hi ​@angel.nunez you can verify a checklist for the upgrade here

https://helpcenter.veeam.com/docs/backup/vsphere/upgrade_vbr_byb.html?ver=120

Anton Gostev starts a thread in official forums where there are some instructions for update to this patch 

https://forums.veeam.com/veeam-backup-replication-f2/veeam-backup-replication-12-3-2-4165-new-patch-delivery-options-t100568.html

The update ISO info (from https://www.veeam.com/kb4696):

name VeeamBackup&Replication_12.3.2.4165_20251006_patch.iso
Size: 1.6GB

So I think maximum 5 GB (patch size + installation file + temp space to unpackage) are needed. Please let us know to needs more 

EDIT: you start from 12.3.2 so you can apply only the EXE patch > uncompresses patch content to TEMP before installing it therefore requiring some TEMP space

VeeamBackup&Replication_12.3.2.4165_20251006_patch.zip
Size: 663 MB 

Thank you so much. As soon as I update, I will let you all know.