If I want to free up space on my Mac itself I can back up the computer, then wipe it, and (with the external drive plugged in holding previous backups) use time machine/finder to see the old stuff?
for instance: backing up photos onto the external hard drive- delegating them- and using the backup to view them if I desire. What’s te risk? Or am I overlooking a detail?
MacBook Air
If something goes wrong with your backup disk, you loose everything that's on it. If your photo's are precious to you, don't relay on a backup disk only. You can move your photo library to an external disk and include that disk in your TimeMachine backups.
Here's how to move your photo library to gain space on your Mac https://support.apple.com/en-us/HT201517
each backup is saved on the backup disk with a date so I can navigate through each backup individually. If I backup the mac on, say, today then delete some files and back up, say, tomorrow. I should be able to see those deleted files on yesterday’s backup - negating the need to save things on two separate drives.
backups aren’t manipulated after they’ve been written right? Unless I do it manually.
That depends on whether you are doing cumulative archival backups such as Time Machine® or overwrite backups used as the default of most backup utilities. In the case of the former, the minimum size of a backup drive should be 3x the capacity of the source drive. In the case of the latter, the backup drive should be the same size as the source drive.
Time Machine® backups can be transferred to another drive by using the Restore option in Disk Utility or other disk cloning software. Other backup utilities can usually be copied, cloned, or other file by file transfers using appropriate utilities such as the backup utility.
It's important to learn how Time Machine® works because despite its apparent simplicity, the underlying engine is quite complex. I'm, personally, not a fan of Time Machine®. The utility I prefer using is Carbon Copy Cloner. It, too, is fairly complex but easy to use for basic backup, syncing, and file copying work.
The words used to refer to a "storage" device varies. I find myself switching between "Disk" and "Drive." Then, we have to deal with the difference between the physical device, i.e., the "Drive" and the logical device, i.e., a "Volume." In the old days a volume was interchangeable with a partition. But these terms are changing with the newer filesystems various operating systems use. If you open Disk Utility and set its "View" to "Display all Devices," then you will see devices listed in a hierarchy. At the top of the hierarchy is the physical drive itself. Below that you see the logical device(s) or volume(s).
Today, we also have to distinguish between Solid State Drives (SSD) and Rotational or Hard Disk Drives (HDD). Both are called "drives."
I hope this clarifies or answers your questions.
Plain_stripe wrote:
backups aren’t manipulated after they’ve been written right? Unless I do it manually.
Correct, although if they only exist on the backup drive they are no longer backups but the only example.
In your experience, what is an adequate size for a backup disk? and have you ever transferred backups from one disk to another?
Specifically I would like to transfer my backup disk to my current storage disk, basically swap the data from one to the other. Currently my backup disk is 1tb and my newer storage disk is 4tb however; logically it may be better for me to get a third larger disk to backup the current backup disk and future backups to. Instead of swapping disks, just transferring to a larger disk. Also correct me on my computer jargon. Im using disk to refer to a storage unit I can't my computer to write onto but.
Time Machine is a backup utility, not a storage utility. If you need a place to store files you cannot keep on the startup drive, then get a separate drive for you storage needs and another for your backup. If you backup using Time Machine, then delete files from your computer, those files will be removed from the Time Machine backup after 30 days or sooner to free up space.
"You can move your photo library to an external disk and include that disk in your TimeMachine backups."
With both the external disk and backup disk connected, will time machine automatically include the iPhoto library stored on the external disk in the backup on the backup disk?
An external disk is not by default included in a TimeMachine backup, but it is easy to include it:
How to move backups to another drive: https://support.apple.com/en-us/HT202380
If a TimeMachine backup disk is getting full, Time Machine deletes automatically the oldest backups. If your TimeMachine backup disk has minimum 3x the volume of the amount of data you have to backup, that’s fine
Some more info: https://support.apple.com/en-us/HT201250
Back up best practice/ advice.
