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I have a virtual machine (Vmware) in external disk. When i want to work with it, i am copying it to my hard disk and when i finished my job i am recopying vm from harddisk to external disk.

Is there any way to do this easly? If there is any way to copying only the differences between them, it would be nice, because i won't have to wait 35Gb transfer time.

Thanks in advance.

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this tutorial shows how to backup the incremental or differential in two minutes-i have not tried it-good luck backupchain.com/… –  mic84 Nov 8 '10 at 12:53
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3 Answers

up vote 1 down vote accepted

I use rsync on my Unix box to copy the latest over to the backup. It only transfers data that differs.

For Windows Microsoft has a program called robocopy that does a similar thing. It is part of Windows newer than XP. For earlier it was part of Windows Resource Kit. The rsync page does list a windows version available elsewhere but I have never tried it.

Inn both cases stop running that machine under vmware before syncing.

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You could use the diff utility to find the differences between two files, then the patch utility to apply those changes to the copy on the external hard drive. Diff will need to analyze every byte in both files, so it may be no faster than copying the file. However, disks and file systems tend to optimize reads over writes, so it is worth a shot.

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If this is Unix as I think patch and diff are - much easier to use rsync which will only copy over the bytes needed all in one command –  Mark Nov 14 '10 at 22:03
    
Diff performs poorly on gigabyte-sized and non-line-based content. If you really want to go down the diff+patch route, I would suggest using xdelta.org which is designed to handle large, binary files. –  ephemient Nov 14 '10 at 22:41
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Why are you bothering with all the copying? Just leave the VMDK on your main drive, or run it directly from the external drive. I have run VirtualBox VMs off a USB2 drive and it wasn't especially slow once it started up.

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I copy it to have a backup - i usually onlycopy from hard disk to external and not both as the OP does. –  Mark Nov 14 '10 at 22:43
    
In that case, why not do the copying after using the VM, so you don't have to wait for the copy to complete before working? –  CarlF Nov 15 '10 at 19:37
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