How to back up an external hard drive?

[Thunderbird]

I've just been backing up my files and folders on a stick up to now, but I'm ready to get a proper external hard drive.

My needs are simple, so I don't want nor need a NAS. I am a single home user, not on a network. I also find most cloud subscriptions too expensive.

What I would like to do is get an external hard drive, and back this up to another drive which I will store off site. I want to be able to update the off-site drive regularly (weekly/monthly). I figure I will accumulate 4TB over the next 5 years.

Questions:

1. Can I do this with by putting my external HDD in some kind of RAID configuration? Can I hot swap a disk with data on it in RAID 1, or does the disk I am swapping in have to be new and clean? If I have a 2-bay (or more) hard drive enclosure, I want to be able to switch out one of the drives for the off-site drive in order to update it. Is this possible?

2. If it's not possible, should I just have one external hard drive and copy it to my off-site drive? How do I do that?

3. So basically, I want to be able to copy what's on my external hard drive(s) to my off-site drive on a weekly/monthly basis. What's the simplest and cheapest way to accomplish this?

 

[Fishrrman]

Before going further, what are your "storage needs" (in terms of gb) right now?

What I'd suggest:

Get a 2tb HDD or SSD (in a USB3 enclosure).

Use a cloning app such as CarbonCopyCloner or SuperDuper.
Both are FREE to download and use for 30 days.
Try either one or both -- if you don't like it, just erase the drive and try something else.

Either one will create a bootable clone of your internal drive.
You can mount the backup right in the finder, or boot from it (it will look EXACTLY like your internal drive does at the last backup).

You can periodically update the clone (only changed files will be copied), so that it always reflects your source volume.

I would maintain TWO cloned backups:
- first one kept nearby for emergencies
- second one kept "offsite" for disasters (house fire, etc.)

 

[hobowankenobi]

Traditionally, before cloud backups, it was common for small businesses (and anybody trying to protect against catastrophe) to rotate backup drives.

Typically plan:

1. Use a good software tool to backup all data, regardless of live location (multiple drives or partitions) to a backup destination drive at a regular interval.
2. Rotate the destination drive at regular interval.
3. Store the destination drives not in use off site, or in a fire-proof safe.

This plan covers several risks:

• Disaster - Fire, flood, earthquake, aliens, etc. (off site, or secured and fire/flood resistant)
  
• Redundancy - Corrupt data, damaged drives (history of data/previous versions of files, and multiple copies on different drives)
• Expand-ability - Easy to grow the backups with newer/bigger drives

Any good backup tool will let you backup to multiple drives, will allow scheduled backups to run automatically, and will give you a report of any issues so you don't have to constantly manually monitor it.

Going NAS solves many problems and allows automation.....but does not (easily) solve the off-site requirement.