Fedora13 showed 128 TB /proc/kcore on 2GB RAM

Bill Davidsen davidsen at tmr.com
Wed Jul 14 21:12:01 UTC 2010

Chen, Helen Y wrote:
> Hi,
> I am running Fedora 13 with the kernel, and am trying 
> to make an ISO image of my hard disk for other use.  Unfortunately 
> “mkisofs” failed because /proc/kcore exceeded its 4GB file size limit.  
> In fact, the size of the kcore on my  system is shown to be 128TB, and 
> the machine itself only contains 2GB of RAM.  Has anyone experienced the 
> same problem?  BTW, the kcore files on my redhat machines reflect the 
> actual RAM size as it should be.   Also, does anyone know why “mkisofs” 
> even tries to copy a virtual file into the ISO image it is creating? 
If "other use" means non-Linux, you will have to exclude the things others have 
mentioned. You will lose some information going to ISO-9669 format, you may not 
care. If you want a real backup, loop mount a 4G file with an ext2 and copy 
everything to that, preserving ownership, etc. Then unmount and burn to a DVD. 
Linux will be happy to mount an ext2 DVD and all permissions and ACLs will be 

Note, I'm just typing this in, engage brain before copying!
  # cd /tmp
  # dd if=/dev/zero bs=1M count=4k of=bkup.ext2
  # mke2fs [options] bkup.ext2
  # mount -o loop bkup.ext2 /mnt/loop
  # for n in / /boot /home; do cp -ax $n /mnt/loop/; done
  # umount /mnt/loop
  # growisofs -Z /dev/dvd=bkup.ext2

I do similar stuff, although if I really care about the data, I often make the 
loop file smaller so I can add dvdisaster software ECC to the image.


Bill Davidsen <davidsen at tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot

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