Primary requirement in a end point backup and recovery solution:
•   List out the number of users and data size per users.
•   What type of file should be backed up from the end devices?
•   What should be the retention period of backed up data?
•   Plan for storage media to backup data (disk / tape / cloud).
•   Depend on data size, provide the Hard disk sizing if it is on-premise.
•   Highly recommend: Dedicated server for backup solution software.