I have Ubuntu 16.04 and have recently setup a VM with 16.04 as well via Virtual Machine Manger. I'm using the GUI for the program. I want to backup the VM disk image externally so in case my machine ever fails I'll still be able to boot the iso in another instance.
I copied the disk image to another directory on my local machine to avoid damaging the original file in anything I was doing. To do so I used "cp -a /source/. /destination". I then used "chmod -R ugo+rw /imagefile/" to give full open permissions to the file. I did this to negate any possible permission issues in the process. I have the installation fully encrypted so I'm not terribly worried about it. I then hooked up a standard drive to a USB drive dock and proceeded to use "pv /source/ > /destination/" to copy it over to the drive.
So first I tried to import/open the image file in VMM directly from the drive on the dock. It gave me a few error prompts in the process that all were linked to permission issues and then ultimately failed importing. I ran "chmod -R ugo+rw /externaldrive/imagefile/" again to make sure permissions were completely open. I tried to mount it again with the same result. Next I used pv to copy the image file back from the external to the local machine. I then mounted the new copy residing on the local machine in the VMM and everything worked fine.
So either you can't mount from an external drive or there is something I'm not understanding about permissions here. Forgive me for my ignorance here, I'm still nothing near a linux guru. My main concern is losing this host system and going to try to mount the backup on another system only to never be able to use the VM image as permissions are tied to a then deceased and inaccessible account/machine.
I copied the disk image to another directory on my local machine to avoid damaging the original file in anything I was doing. To do so I used "cp -a /source/. /destination". I then used "chmod -R ugo+rw /imagefile/" to give full open permissions to the file. I did this to negate any possible permission issues in the process. I have the installation fully encrypted so I'm not terribly worried about it. I then hooked up a standard drive to a USB drive dock and proceeded to use "pv /source/ > /destination/" to copy it over to the drive.
So first I tried to import/open the image file in VMM directly from the drive on the dock. It gave me a few error prompts in the process that all were linked to permission issues and then ultimately failed importing. I ran "chmod -R ugo+rw /externaldrive/imagefile/" again to make sure permissions were completely open. I tried to mount it again with the same result. Next I used pv to copy the image file back from the external to the local machine. I then mounted the new copy residing on the local machine in the VMM and everything worked fine.
So either you can't mount from an external drive or there is something I'm not understanding about permissions here. Forgive me for my ignorance here, I'm still nothing near a linux guru. My main concern is losing this host system and going to try to mount the backup on another system only to never be able to use the VM image as permissions are tied to a then deceased and inaccessible account/machine.