Skip navigation

verifying a cloned drive size and whether it is OK.

285 Views 8 Replies Latest reply: May 2, 2012 7:27 PM by X423424X RSS
hotwheels 22 Level 1 Level 1 (0 points)
Currently Being Moderated
May 2, 2012 9:54 AM

i am hoping to get a little help on verifying my cloned drives which i have been setting up using CCC. i have not had a chance to "zero out" the drives before running these backups but i /do/ plan to re-read this documentation and do this for the macbook pro when i switch out what i am using now.


i am about to BOOT into these two drives and i thought to empty the trash on the Mac Pro and take a look at the sizes of these two backups and i am wondering if anyone can please tell me that this looks fine but also to tell me if there is anthing else i should check other than simply directly booting into these two drives.


the first image is my mac pro HD, the second my external backup and the third is my internal backup.


would anyone mind .png .png .png


  • The hatter Level 9 Level 9 (58,535 points)

    Why not use OmniDriveSweeper to see where


    A clone does not copy temp and cache files from the system (it does copy the user's)


    2/3 is "full" for all tense and purpose


    And ~600GB on each is "close enough"


    The test is in the taste: repair the drive, then do a safe boot once, then restart and let it do a full normal boot.

  • X423424X Level 6 Level 6 (14,190 points)

    I don't understand your problem.  The two clone's (I still wish you would embed your pictures in your posts) are about the same size (595.63 and 595.64) and your original is 601.47.  A difference of only about 6GB.  If your clones pass Disk Utility, and they are you can actually boot from them, why are you worried about a 1% difference?  If you don't trust the cloning software you are using for backups then I don't know what to tell you.


    As mentioned above, "clones" are not true bit-for-bit copies.  They are file copies.  Not all the files are put in the same physical block on the copy so there are allocation differences.  Even more significant, also mentioned above, is the backup utilities are smart enough not to copy stuff that is just going to be recreated anyhow if you use those copies.  There's temporary files (e.g. like /tmp), some caches, and even more significantly there's the swap space (backing store, virtual memory, pick your favorite name).

  • The hatter Level 9 Level 9 (58,535 points)

    Do a safe boot if you have an issue like an unclean shutdown or restart.


    focus on having backups and clones from before the problem is any


    4 yrs ago you had to rely on if anything Disk Warrior instead of Disk Utility.

  • X423424X Level 6 Level 6 (14,190 points)

    hotwheels 22 wrote:


    can i just ask you additionally if i should be running a disk utility on my volumes every once in awhile to check them and then to repair them if necessary and whether there is any other "preventive maintenance" that I should be scheduling in order to play it safe...?


    Using DU every once in a while is basically what I do.  If I am having one of my "real paranoid days"™ (not that often fortunately) I will even test the boot backup to make sure it boots.  But I've learned to trust CCC to reliably do its backups (you have to learn to trust your backup program no matter which one you choose).


    The advantage of doing the DU's every so often is that if there is a problem, the odds are pretty good that DU can fix it.  If you don't do this then disk errors may compound to a point where DU may not be able to fix them.

  • X423424X Level 6 Level 6 (14,190 points)

    You're welcome.


More Like This

  • Retrieving data ...

Bookmarked By (0)


  • This solved my question - 10 points
  • This helped me - 5 points
This site contains user submitted content, comments and opinions and is for informational purposes only. Apple disclaims any and all liability for the acts, omissions and conduct of any third parties in connection with or related to your use of the site. All postings and use of the content on this site are subject to the Apple Support Communities Terms of Use.