[Dirvish] checksum=0 may be causing inaccurate backups!!!

Keith Lofstrom keithl at kl-ic.com
Fri Jun 22 22:58:41 UTC 2007


Keith Lofstrom - keithl at kl-ic.com wrote:
> So, a request!   Could some of you try adding the line:
>
>checksum: 1
>
>To your dirvish master.conf file, so that dirvish runs this way
>over the weekend?  

On Fri, Jun 22, 2007 at 07:46:30PM +0300, dirvish.yklein at spamgourmet.com wrote:
> I added the checksum: 1 directive to some of my dirvish.conf files, and 
> it found some files that hadn't been updated in a long time. Among my 
...

Thanks, Yoav!


I found out what was causing the vast bulk of my files to checksum
differently - "prelink" on my redhat-derived system.

To quote the first paragraph from the man page for prelink (8):

       prelink is a program which modifies ELF  shared  libraries  and
       ELF dynamically linked binaries, so that the time which dynamic
       linker needs for  their  relocation  at  startup  significantly
       decreases and also due to fewer relocations the run-time memory
       consumption decreases too  (especially  number  of  unshareable
       pages).  Such  prelinking  information  is only used if all its
       dependant libraries have not changed since  prelinking,  other-
       wise programs are relocated normally.

For more information, see http://en.wikipedia.org/wiki/Prelinking 

The program loader is smart enough to deal with corrupted prelink 
tables, so my old backups (with different prelink information) are 
still valid.  

I am going to revert my systems with prelink -ra, then turn it off,
then run another set of "checksum: 1" backups.  Yes, prelink speeds
up program loading my systems, but it is not necessary, and it bends
dirvish and it breaks the file integrity monitoring system I am using.
I prefer slow, stable, and secure to fast and fragile.

Keith

-- 
Keith Lofstrom          keithl at keithl.com         Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs


More information about the Dirvish mailing list