Time machine backup of existing OS on new external hard drive

I am familiar with the process of transferring an old time machine backup to a new external hard drive. Is there any reason I can avoid this and simply create a new TM backup on my new external drive, then reformat the existing drive to use as my media storage? I just don't see why I need to copy 1.5 TB of data to a new drive when I can create the "same copy" using much less space. This assumes there are no existing corrupt files on my OS.

If I am understanding you correctly I've done that several times. The new backup will, of course, only go back as far as when it is created. My suggestion would be to only delete the "old" backup after the "new" one is complete. Just in case something goes wrong with the new backup.

Sure, you don't have to back up the backup if you don't want to. The key advantage to the Time Machine backup is that you can restore something you may have modified or deleted months earlier and only realized much later that you need/want that older something (has happened with me). But if you don't want that extra safety net, it's entirely up to you.

Thank you both for such quick and informative replies. I am about to upgrade both my iMac and MacBook Pro from SL to Mavericks. Would this have any further impact on your advice of having a TM copy that went as far back as the hard drive? Per Lifeisabeach's advice, sounds like all the more reason.

Second question is does the amount of data on my TM backup disk have a significant effect on how quickly it will sync and backup? Since TM only backs up changes since the last backup it's probably not a big deal. At least that is my understanding of how TM backs up. Thanks again for your help.

I backup to a hard drive attached to my Time Capsule. Once the initial backup is complete I usually don't notice that a backup is occurring. The only issue I've noticed is that once in a while the drive is slow to mount and if I am running iTunes there may be a brief pause. Since it's not a common occurrence I am wondering about that drive. It's an older one and may be starting to let go.

For m the issue of whether to keep the older backups around boils down to answering a couple of questions:
1. Is there something in that backup that would not be in the second backup. Say, for example I modified a file one month ago. The original and modified versions will be in the old backup. The new one only has the modified version.. Do I need the old one?

2. Do I have the drive space to keep both copies?

Thanks Slydude. The only instance I can think of where I might need to go back(which I never have) would be with my SketchUp files that have had multiple modifications. Otherwise, most all my important files are kept either in Box or Dropbox.

This seems to be one of those instances that would support the use of Carbon Copy, Super Duper, Flashback, etc and just reboot from a clean and "complete" copy of my hard drive. Opinions vary on this of course as we all know.

[possible new thread]
With both my machines a few years old and already maxed out with memory upgrades, I would like to reformat and reinstall a "clean" copy of my hard drive in hopes to optimize performance a bit. It seems like TM impedes this process by keeping such a large file or am I missing something? This applies to my scenario of course, which is that I don't believe I will need to get an old version of a file(famous last words).

Since I'm 1). about to upgrade from SL to Mavericks, 2). I'm in need of upgrading my TM backup drive, and 3). I'm considering reformatting and reinstalling a copy of my existing hard drive to optimize my machines performance(and I don't feel I need an older version of my hard drive), is copying over my entire TM backup really the best option or should I purchase cloning software and create bootable copy, reformat, make TM backup to new external HDD, then install Mavericks? I realize we've just entered into new thread territory here, so my apologies. Thank you for all your insight! Wish I had joined Mac Forums long ago.

I just thought I'd mention a method from another forum that has worked very well for me and others before you start a [possible new thread]. Especially for increased performance. And you end up with a bootable backup clone as well.

The procedure is to make sure everything is up to date on your boot drive and then use CCC (Carbon Copy Cloner) to create a clone on an external drive.

Then boot from it and then 'nuke & pave' your normal boot drive. Erase/Partition and format the normal boot drive and run the zero out once option. DO NOT SKIP THIS STEP.

When it's all done and finished, use CCC to clone back the cloned backup to the normal boot drive and then set it as the normal Startup Volume.

I couldn't believe the speed improvement when I first did this with my iMac, and I have done so later as well, and with other users Macs with the same improvements.

PS: I haven't used TM for ages and I've seen it goof up just too many times thanks, but do use CCC for regular backups and one can use its archiving option for old deleted files if desired. Sort of like a TM backup archiving does.

No TM for me either. SuperDuper, another cloning tool, like CCC makes a bootable copy to the external drive in case of emergencies.

Thanks for all the help guys. Will look into a combo of TM and a bootable cloning software option.

harryb2448 said:

No TM for me either. SuperDuper, another cloning tool, like CCC makes a bootable copy to the external drive in case of emergencies.

Click to expand...

I guess I'm paranoid Harry, because I use both methods; Time Machine and CCC. Also take note of what LAB stated above about going back in time to dig out a file from 6 months ago (as an example). You can't do that with just SD or CCC unless you want to keep a bunch of archives on hand.