Re: [cobalt-users] disk usage

[Tim Dunn <tdunn@xxxxxxxxxxxxxxxxxxx>]

> > > >hmmm! Norton Ghost?
> > > Can you suggest an image tool that does? [run on linux]
> >dd
> 
> You lost me here.  man dd... "dd - convert and copy a file"
> Imaging tools create duplicates of hard drives on other hard drives or media.

This is unix.  "Everything is a file" is the mantra.  /dev/hda1 is a
file.  See?

The hard part using dd isn't mirroring a filesystem onto a disk (form
small values of "filesystem"), it's how to get the system to boot up
the disk when things go the blazes.

F'instance, for one "poor man's raid" solution a friend and I came up
with, we just popped two identical drives into a Sun workstation.  Every
night at some ungodly hour, it'd dd the overlap partition (s2) from one
disk onto the other.  The solution wasn't perfect.

1) there's a failure window - if the system gets zapped after it's 
   started writing to the backup disk, you now have twice as much
   useless hard drive real estate

2) you still need to do the installboot.

3) you couldn't just get on the terminal and tell the box to 
   "boot disk1" - all the device files in /etc/vfstab still pointed
   to corresponding loccations on the first drive.

Still, at worst, you could get to the box, pop the cover, and swap the
drives, then reboot.  Better than nada.

tim

-- 
Sysadmin Rule #14: If it's not on fire, it's a software issue.