Transfer database backup from Production to Staging during business hours We have a nightly Production to Staging database sync that failed this morning. I need to copy a backup from 1 Production server to 1 Staging server and I'm not sure of the best way to do it without interrupting services or affect performance.

The backup is 15GB and the servers have a high speed connection between them. Would it be best to simply copy the backup from Production to Staging and perform the restore manually, or would this affect performance too much?
Usually copying your latest database backup (from the production backup location) to an area where you can restore it over the top of your staging area should have no effect on your production database.  The only time where this would affect it is if you're storing the backups on the same drive(s) that is hosting the live database, but hopefully you're not.  In this instance, the file copy operation will just generate extra, and competing, I/O with your normal database operations.

Your question doesn't provide enough context around how this sync process works, but a 15GB file copy isn't usually large enough (in my experience) to crash a server or cause any severe performance degradation.