Lost all Data

Matthew Dillon dillon at apollo.backplane.com
Tue Aug 11 10:17:42 PDT 2009

:but my /dev on the second disk has more files than /dev on the first disk.
:I have updated the base system on the second disk also using chroot .
:Is it because i have not booted from the second disk after the upgade?

    It's just because DEVFS is mounted on one and not mounted on
    the other.  With DEVFS we no longer need anything in the dev
    directory since the DEVFS mount will simply overload it.  An
    all-new installation of the system will leave the original /dev
    in the filesystem (prior to mounting DEVFS) empty.

    An upgrade leaves the original contents of /dev intact.. not because
    I want it to be intact (I'd rather delete it)... but because it is
    difficult to delete it on a live system since we can't unmount DEVFS.
    The only way to delete would be to do a localhost NFS export for /,
    mount it somewhere else, and then the original /dev would be exposed
    and accessible for deletion.

    So, simply put, you have DEVFS mounted on top of one filesystem
    but not on top of the other.  The original contents of <fs>/dev
    is no longer relevant to the system now that we have DEVFS.

    If you want to mount DEVFS in both places you can do so with
    mount_devfs, or even mount_null.


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