When there are many websites during daily backup (for example, more than 200 websites), it is impossible to guarantee that every website is backed up

I found that when I have many websites on one server, the daily backup cannot be completed completely (that is, all websites are backed up). It may be that after a certain point in time, the websites that have not been backed up on the day of backup will no longer be backed up. This process may be repeated the next day. The background does not show which websites have not been backed up. This puts my data at a very high risk of being lost. Is there a way to solve this problem. (I use sftp for backup)

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