With a large server, I don't have enough time in the day or enough CPU cycles to back up this server in a reasonable amount of time. So, how are we going to do that? You have to take a step back. Really, what is a backup? Its just an alternate copy of your data for restores. CDP and near-CDP solve the problem in a different way. They don't do the full backup or the nightly backup in the traditional sense. So CDP and near-CDP essentially remove the problems associated with large server backup. Because you are backing up the data as its changing, CDP and near-CDP work really well when you are backing up a large data set.
With CDP, you are transferring data to the backup system literally every second so you are spreading out the load over the course of a whole day. With near-CDP you have the option of doing it that way or you can transfer it in small chunks -- say every hour you transfer the blocks that were changed during that time. Either way, you are moving a significantly smaller amount of data than you are during a traditional backup.
One could argue that CDP and near-CDP products are server-free backup in a general sense,
Check out the entire Server-free Backup FAQ.
This was first published in May 2008