The big issues with backups IMHO is getting a consistent snapshot.  If you 
start copying a large data file, and it changes after you've copied the 
beginning, you're screwed.

Over the years, I've generally adopted a smash-and-silver backup plan. Namely, 
I run mirrored during normal operation. To create a backup, I silver a 3rd 
mirror. Once the 3rd mirror is silvered, The file system can be frozen 
momentarily, and the 3rd mirror is seperated from the set. A backup is now made 
from this "smashed" silver. Repeat the process for as many filesystems as 
necessary. To work 100%, it requires cooperation from the filesystem/kernel (to 
some degree)

Other backup schemes I've used involved BCL's (Block changed logging), that 
allow the admin to only backup up those blocks that have been updated since the 
last master. This is a GREAT space saver for large data farms with low update 
rates. I tend to work on larger multi-terrabyte systems, so minimizing backup 
times is very important.


Are you planning on your backup scheme being able to handle "hot" backups?

 - jim

On Sat, 23 Jul 2005 16:25:43 -0700 (PDT)
Sebastian Smith <[EMAIL PROTECTED]> wrote:

> Hi All,
> 
> Over my short sys admin career I've found few backup packages I like... 
> and none I'd pay for.  As such, I'm bent on creating my own system that is 
> flexible, scalable, portable (maybe), and robust.
> 
> I've been using a modified version of the "backup to a central backup 
> server with 7 day incremental" backup script from rsync's "examples" page 
> for over a year now:
> 
> http://samba.anu.edu.au/rsync/examples.html
> 
> It works great, and is easily augmented with other scripts to backup to 
> CD, DVD, tape, or whatever.  It doesn't offer a restore function, but, 
> since it stores backups as exact copies of existing files (the ideal 
> method... IMHO), replacing files is easy.
> 
> The primary problem I've found with this script is that it has to be 
> modified for each installation (effects a lot of the qualities I'm looking 
> for in backup software).  So... I've started generalizing the script, and 
> have begun adding features I want... which are:
> 
> - Multi-source, and Multi-destination (including to/from remote hosts via 
> ssl tunnel)
> - Optional Parallelized execution
> - Copy referent of symlinks 
> - Preserve permission, ownership, etc
> - Quiet operation (no output to stdout, stderr)
> - Error handling
> - Notification of errors
> - Detailed logging
> - Easy modification of scripts
> 
> I'd like to know what everyone else would like in backup software, as when 
> I'm done I will release it to the community.
> 
> I'm currently scripting in Bash, but will probably release in Perl, and 
> Python as I need practice in all.
> 
> - Sebastian
> 
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