I have a small NAS where I back up all my data. Being a wee bit paranoid, I take a nightly snapshot (using rsnapshot) of all the data too. I also sync the data to a Google Drive account. So far so good.
The NAS is, amongst other things connected to a box running FreeBSD. Ah, the joys of user IDs across multiple machines. To cut a long story short I need to fix some ownership permissions. So, with narry a thought I did a quick:
chown -R psmith /volume1/homes/psmith
Ownership problems fixed!
Alas, a fair few files were touched by the chown, and now the NAS is busy sync 30,000+ files to Google Drive. That is going to take a while. Previous experiences tells me it will take about a week to transfer the 1Tb or so to Google Drive.
Interestingly, the backup using rsnapshot was not impacted that way. The incremental change in data was on 11Gb, which–on a daily basis–is not unusual.