MacOS – Alternative backup solution for a mac

backupmacmacostime-machine

I know that we can easily use time machine. However, i wonder if there exist any other way to backup the data on my macbook? Since I do a lot of modification to the system and sometimes make it has kernel panic, I would need the backup program to be able to restore everything from a bootable cd (the backup file can be on the hard disk).

So, if your solution offers a bootable backup, that's great, but I'm more interested in equivalent functionality of Time Machine where multiple snapshots are available.

Best Answer

To create bootable backups which contain everything including system files, you may want to look at Carbon Copy Cloner or SuperDuper.

Modes and ownership

Ideally, use chmod(1) and chown(8) to have the mode and ownership, of the copy of the disk image, consistent with how Mountain Lion normally creates a local disk image for Time Machine.

Example

GPES3E-gjp4-1:~ gjp22$ sudo ls -al /Volumes/tall/com.apple.backupd/GPES3E-gjp4-1.sparsebundle/
Password:
total 16672
drwx------@ 3 root   staff     10  7 Jun 19:07 .
drwxr-xr-x  8 gjp22  staff     10  6 Jun 18:57 ..
-rw-r--r--  1 root   staff    500  7 Jun 18:03 Info.bckup
-rw-r--r--  1 root   staff    500  7 Jun 18:03 Info.plist
drwx------  2 root   staff  78855  7 Jun 19:07 bands
-rw-r--r--  1 root   staff    444  7 Jun 18:02 com.apple.TimeMachine.MachineID.bckup
-rw-r--r--  1 root   staff    444  7 Jun 18:02 com.apple.TimeMachine.MachineID.plist
-rw-r--r--  1 root   staff   1473  6 Jun 21:28 com.apple.TimeMachine.Results.plist
-rw-r--r--  1 root   staff  10698  6 Jun 22:24 com.apple.TimeMachine.SnapshotHistory.plist
-rwx------  1 root   staff      0 19 Mar 19:36 token

– and for each band, you should have:

-rw-------  1 root  staff

Attaching the copy of the disk image

With Terminal, for the example above:

sudo hdiutil attach -readonly /Volumes/tall/com.apple.backupd/GPES3E-gjp4-1.sparsebundle/

If you use Terminal from within Recovery OS: you'll probably not need the sudo prefix to the command.

Additional detail

… whether I can still restore …

You require:

a copy of a Time Machine destination, a copy that will be good for restoration
not an additional Time Machine destination.

Assumption

You wish the copy to be usable, for restoration only, in the event of loss or failure of the Time Capsule.

If the disk is attached from a local image where modes and ownership vary from the norm for a local image:

OS X or Recovery OS might use that disk without difficulty; I can't be certain.

Thoughts

If you're preparing for the possibility of loss or failure of a Time Capsule – and restoration from a copy of what was there – then think a step further, to backing up without the original Time Capsule. (If you wish the copy to be writeable by Time Machine, that could be a separate question.)

All things considered

It's probably quicker and simpler to use the external hard disk, or a part, as a Time Machine destination.

MacOS – How big should the Time Machine backup drive be

You probably want to check out this website for the most information, but here is the answer to your question, quoted from the website above:

1. How big a drive do I need for Time Machine?

A general "rule of thumb" is, to keep a reasonable "depth" of backups, Time Machine needs 2 to 4 times as much space as the data it's backing-up (not necessarily the entire size of your internal HD). Be sure to add the size of the data on any other drives/partitions you want to back up.

But this varies greatly, depending on how you use your Mac. If you frequently add/update lots of large files, then even 5 times may not be enough. If you're a light user, you might be able to get 1.5 times to work, but that's subject to problems any time a large backup is needed.

And, of course, the larger the drive, the more old backups Time Machine can keep for you. A drive that's too small may only have room for a few weeks (or even days) of backups.

Unfortunately, it's rather hard to predict, and most of us have a tendency to add more and more data to our systems over time, so if in doubt, get a bigger one than you think you need now.

Also, there are some OSX features and 3rd-party applications that take up large amounts of backup space, for various reasons. See question 9 for details.

This is a trade-off between space and how long Time Machine can keep its backups, since it will, by design, eventually use all the space available. But it won't just quit backing-up when it runs out: it starts deleting the oldest backups so it can keep making new ones. Thus, the more space it has, the longer it can keep your backups.

If your backup disk is on the small side, and Time Machine needs to do a very large backup, either because you've added or changed a lot or done something like an OSX update since the previous backup, you may get one of the messages in Troubleshooting item #C4 (which one depends on exactly what happened, and which version of OSX you're on.)

My Answer

Then it'll only take a snapshot that's about 120GB in size, and while that same snapshot will grow over time as I take more recent snapshots of my system, it will never go beyond 500GB because that's the maximum size of my internal HDD.

No, not quite. The 1 TB hard drive will be filled up because Time Machine keeps your backups and deletes them once your hard drive is filled. There is more than one backup stored on that hard drive. As stuffe pointed out as well, Time Machine allows you to restore to a previous backup, since Time Machine may keep 7 or 8 backups on that 1 TB hard drive.

I'm asking this because I want to know if I should use a separate external HDD for storing my actual files.

Yes, you should. You should be dedicating a drive to Time Machine. Here is the quoted answer from 3 in the website I linked above:

3. Can I use my Time Machine disk for other stuff?

Yes. Time Machine will not delete anything you put there. But it's not a good idea to put anything else important on the same physical drive, unless you back it up elsewhere. When (not if) that drive fails, you risk losing it.

If you want to do this anyway, it's much, much better to partition an external drive into 2 (or more) parts, also called volumes. Assign one to Time Machine, for its exclusive use for backups; use the other partition(s) however you want. To use a new drive, or one you don't mind erasing, see question #5. To add a partition to an existing drive that already has data on it, see question #6.