The component sizing that should be adjusted is the physical storage in the repositories. The repositories are the backup storage locations where Veeam Backup & Replication stores backup files, VM copies and metadata for replicated VMs1. Increasing the retention period from four to five years means that more backup files will be kept on the repositories, and thus more storage space will be required. The other options are not affected by the retention period change, as they are either related to off-site backups (option A), Veeam Backup & Replication server performance (option C), or backup proxy performance (option D). References: Backup Repositories.