Re: UNS: Re: Taking mirror Backup of SVN Repos through 3rd Party Software

On 6/30/2011 10:46 AM, Andreas Krey wrote:
> On Thu, 30 Jun 2011 10:09:43 +0000, Les Mikesell wrote:
> ...
>> A backup made in an inconsistent state should exactly resemble the disk
>> files if the system lost power or crashed for another reason at that
>> point.
>
> No, backups can contain inconsistencies that are impossible to
> create with a server crash. When, say, the svn server writes
> file A and B with a synchonization point in between, it is
> still possible for a backup to contain the old A and the new B.
> This can't happen in a crashed filesystem.

I think you are being way too optimistic about real-world filesystems
and disk and controller caches. It is possible to make a system that
behaves with the ideal behavior you describe - and maybe many do in
terms of the filenames and directory entries. But I'd guess that the
majority don't really get this right with the data contents of those files.

-- 
   Les Mikesell
    lesmikesell_at_gmail.com