I have a camera system with a NVR. It has the ability to backup using FTP. I’m going to use the newest Rasberry Pi to accomplish this. If someone breaks in, they could steal the NVR. I’ll have a much easier time concealing and securing the Pi. I won’t be backing up continuously, only motion alarms for a few cameras for various parts of the day. Two questions....

1. I want to use an external SSD. Most seem to not have an external power supply. From what I read, the Pi won’t be supplying enough juice to power it. Thoughts? I could get a huge microSD card but I don’t know if that’s suitable for this use.

2. I’m brand new to Pi but I know the possibilities are endless. Does anyone know of a way that I could get the Pi to overwrite data as it comes in through FTP? For example, once the storage is full, I would want it to write over the oldest data.

The Pi can easily handle a usb thumb drive in addition to the OS on the SD card.

Ftp servers can be set up to allow files to be overwritten, but what you're asking for is FIFO cleanup.  Pretty sure you could write a script for that in Linux.  I'm doing it with some batch files and solways freeware on my Filezilla on Windows servers.

I’ll have to do research on how to write script in Linux. I’m brand new to this, but thank you for the terminology!

Would I be better off just buying a 512gb microSD card and put the OS on it and have the NVR footage save to that? I’m averaging about 1.5gb a day of data being sent via FTP. I don’t know if SD cards were built for this or if the slower write speed matters?

Don't trust a micro SD card for anything you want as a backup.

I think you're going to want an externally powered ssd drive for that application.

Both for performance and reliability.

These may or may not be useful. Info for booting from and using the full capacity of SSD on Pi. Also some info on drives that will work along with a how to on getting it all setup using two different methods. I dont have anything to add about setting up the rest of what you are wanting to do, but these proved useful to me for my uses.