Front page | perl.perl5.porters |
Postings from May 2003
On Thursday, May 22, 2003, at 02:59 AM, Eric Browning wrote:
> Mike and Dan,
>
> I've uncovered a serious bug in psync and CCC, or the interaction of
> the two. When my firewire backup drive is not connected and a
> scheduled task runs it places the backup somewhere hidden on my
> internal drive of my powerbook. I used to have 18G of free space but
> I've watched it decrese over the last few days to 3.23G, today, it was
> 3.31 before the scheduled task ran.
What happened was that psync backed to the same drive.
> Where is this hidden location and how do I clean it out?
If the name of your firewire drive is 'FireWire', check
'/Volumes/FireWire' WITH YOUR DRIVE disconnected. Erase that directory
and reconnect FireWire.
The problem is that psync works on paths. This is a classical *nix
file system problem. Even when you unmount the drive it "works" so
long as the patch remains the same.
This is both a blessing and curse. It is a blessing because you can
work on file systems regardless of the media. It is a curse because it
sometimes leads into problems like this.
However, there is a simple way to check if a given paths is on a same
volume or not. Try a one-liner below.
perl -le 'sub d{(lstat(shift))[0]}; print d(shift)!=d(shift)' path1
path2
Here is how it goes.
> % perl -le 'sub d{(lstat(shift))[0]}; print d(shift)!=d(shift)' /
> /Volumes
>
> % perl -le 'sub d{(lstat(shift))[0]}; print d(shift)!=d(shift)' /
> /Volumes/Backup
> 1
It prints 1 when different and empty line if same.
Even simpler one is as follows;
mount | grep /Volumes/Backup
print a line if /Volumes/Backup is actually mounted.
So far psync makes sure not to back up files which is located on the
different volume ON SOURCE. But it does not check if the DESTINATION
VOLUME is different from the source. It is deliberately made so that
you can use psync for partial backups like "psync ~/Library/Preferences
~/Preferences.bak". Maybe I should add an option to make sure that
source volume MUST be different from the destination volume....
Dan the Man with Too Many Modules to Maintain