[Gb-ccb] An external CCB USB connector?

[Martin Shepherd]

On Mon, 21 Nov 2005, John Ford wrote:
> I think the best solution for this is to figure out how to back it up over
> the network.  I don't want to modify the hardware, particularly the
> packaging, at this point.

Understood.

I'll take another look at network backups.  We could actually do this
right now, by simply using the dump command's options for remote
backups. However this is potentially risky, since it would involve
backing up an active root filesystem that might be written to during
the backup. This could lead to backing up partially written files,
inconsistencies in the filesystem superblock etc. I don't know how
significant this is, in practice, but there's nothing worse than a
broken backup, especially if the error is so subtle that it leads to
occasional unexplained strange crashes, long after the original
filesystem has been overwritten by a subsequent backup derived from
the first.

The recommended way to backup the root filesystem of a computer is to
boot into single-user mode, run the sync command to force all
unwritten data to disk, and then assume that the lack of running
networking and other daemons, means that nothing will be written to
the root filesystem while the backup is in progress. We, of course,
would need networking to be at least partially enabled, in order to
perform a network dump. So straight single-user mode wouldn't be
sufficient. However I'm guessing that entering single-user mode, from
the serial console, and then manually bringing up the network
interface, using the "/sbin/ifup eth0" command, without starting any
of the networking daemons, would be sufficient. One would need to
check whether the dump command, or the ssh command that it uses to
send and receive data, might write anything to log files during the
backup.

Martin