[Sussex] Problem writing image to CD

[Stephen Williams]

On Fri, 2005-10-07 at 21:28 +0100, Brendan Whelan wrote:
> Hello,
>  
> I have created a backup shell script which exports a database, gathers
> files, creates a CD image file and then writes it to a CD.
> The shell script is then scheduled to run during the night. There are
> a pair of, logically identical, systems one a Dell tower and the other
> a Dell rack mountable servers. (Fedora Core 3 is used on both
> systems.) The shell script works perfectly on the tower system but on
> the rack mounted machine the CD writing fails. The image to be copied
> is only about 360Mb, I have used different manufacturers CDs but the
> problem persists. I changed the CD drive but the problem persists.
>  
> I have taken an image copy of the offending system and placed it my
> test system with the same type of CD writer which is in the rack
> mountable system.
> To simplify the problem I created a shell script which just
> contains the line which writes to the CD.  When I run the script in a
> terminal window it works. When I run it as a cron job it fails. The
> led on the CD writer flashes for a number of minutes and then goes on.
> The CD cannot be unmounted and the only way to extract the CD is to
> either power the system down and back up or to use a paper clip to
> release the CD drawer. (As an aside small image files can be written
> to the CD using a cron job.)
>  
> Any suggestions as to what might be causing the problem or how I could
> find out more information.

My suspicions centre around power saving. Is apm or acpi set to power
down the CD-RW in the rackmount box and not in the tower box for
example.  Perhaps the user account under which the cron job is run needs
sufficient authority to be able to prevent power down signals from
affecting the CD-RW when a job is in progress? Might be something worth
investigating.

Steve W.


>  
> Thanks, Brendan 
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