I have 4 Macs in my household that have a decent local backup strategy. I am preparing an offsite backup disk and wondering about the best strategy for structuring the offsite backup disk.
I want to protect:
- 4 Macs with a total of 3.75 TB of internal storage. Approx. 80% usage of capacity
- 2 external drives connected to two of those Macs
- 5 TB capacity, 50% used
- 4 TB capacity, 25% used
Potential capacity to be backed up is 12.75 TB, but current data size is 6.5 TB. I have purchased a single 8TB external drive to be taken offsite. Yes 12.75 TB cannot fit in 8 TB, but 6.5 TB can. I don't foresee the external drive usage to increase more than 1 TB in the next year.
Backing up to the cloud is out of the question, as I am working with a 100 GB per month data budget.
- All of the data on the external drives is vital data and large, such as my photography. That alone comprises 2.2 TB
- Everyone in the household makes their living from their Macs. If a big disaster happens, I need to purchase new Macs and get them back to fully functioning in the shortest time possible
Each Mac is currently backed up locally by both Time Machine and a bootable backup via Carbon Copy Cloner (CCC) to separate disks. Since I have these set up already, I'd prefer to stick with these options, but am open to suggestions.
CCC would require partitioning the backup drive into 6 partitions, locking in the amount of data I can backup up for each source. Time Machine (TM) on a single 8 TB partition would allow the free space to "float" to where it is needed as the external drive usage increases. Because of this, I am leaning towards TM vs. CCC simply because of the amount of data to back up.
I would be storing this 8TB disk offsite and bringing it to my house occasionally. I would then connect the drive to each computer, let TM do its job, then take the disk off-site again. I may put a second disk in rotation so that there is never a time when all disks are on-site. See my answer to a similar question https://apple.stackexchange.com/a/381886/146721 for the details of how the rotation works.
Encryption is a must since I cannot guarantee the physical security of the offsite drive. If I go with the TM route for backup, I can encrypt the entire drive with a single password or allow each machine's backup to be encrypted with a separate password. Since these are family backups, I am not terribly concerned with intra-user security, so I am leaning towards a single encryption password.
My existing in-house backup strategy (TM + CCC) should take care of most mundane restoration situations. The scenario I am attempting to cover here is complete disaster, such as the house burning to the ground. In this case, all computers and on-site backups are assumed to be destroyed. In this scenario, new hardware would have to be purchased and restored from the TM backups
Does this seem like a reasonable strategy?