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Re: mkisofs aborts but exit value is 0

scdbackup@gmx.net wrote:

> > -	Damaged CPIO archives are much harder to recover than
> > 	tar archives.
> afio does a good job with that.

But this is very time consuming as it needs to step forward
in 2 byte units while tar may do it in 512 byte units.

> > -	The POSIX cpio format is limited to 8 GB files.
> > 	The SVr4 cpio format is even limited to 2 GB files.
> I urge my users not to store files larger than 2 GB
> in any backup format. Such a size makes readability
> questionable. Not only because of the reader software
> but also because of the rest of the reading system's
> infrastructure.

While this may have been true 1995 when the first large file
support appeared on UNIX, it is no longer true today if you
use the right backup tools.

> Well, in this scenario my own software is the backup
> utility and star is the media image formatter (like
> afio, mkisofs, zip or whatever).

If you do this with mkisofs or afio which are no backup
tools, this may be OK, but if you do this with a program like star
that includes backup support, it is questionable.

> Very good. It's rare that command line utilities
> specify their exit values.
> I meanwhile had found that  exit(-2);  in star.c
> and dared to make my wrapper handle  254  as
> a non-perfect but overall successful program run. 

If you know that there may be tolerable problems, it is better
to use the errctl= option and to tell star to ignore this 
special condition.

> > star-1.4 does not support incrementals.
> > with cpio, or a similar program, this is not possible too.
> But with scdbackup it's possible :))
> Incremental ISO, incremental afio, incremental star-1.4 ...
> on a file-by-file level, not on a rsync level.

Does scdbackup support renamed and removed files?

Star does. It does even in a very efficient way.

> Nevertheless one has to warn users of the increase in
> complexity which is caused by an incremental backup
> scheme.
> It is very convenient at backup time but may cause
> a lot of extra work at restore time.  

Star includes consistensency checks at restore time and warns
you if you try to restore the wrong archive or use the 
wrong order.

> Anyway, compression is nearly a must with large backups
> of system oriented files. Sysadmins tend to hate waste of
> media and of time. Especially if they have to change the
> media every few minutes.

This is why all recent tape drives include "hardware" compression.

> > ACLs are enabled by default on the UNIX file system since 
> > more than 10 years and cannot even be switched off.
> At least for SuSE Linux it is necessary to add options
> to /etc/fstab . This is specific to the particular file
> system type. With reiser or ext2 this would be option "acl".

ACLs have been (silently) enabled on Solaris since 1994.


 EMail:joerg@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
       js@cs.tu-berlin.de		(uni)  
       schilling@fokus.fraunhofer.de	(work) Blog: http://schily.blogspot.com/
 URL:  http://cdrecord.berlios.de/old/private/ ftp://ftp.berlios.de/pub/schily

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