On Fri, Oct 20, 2006 at 05:29:05PM -0700, Don Murray wrote:
> 
> Hi Jon, thanks for the reply!
> 
> Jon LaBadie wrote:
> >
> >"Up" is less a concern to me than "connected".
> 
> Actually for those people the main issue is that some key services (like 
> the email server) are shut down during backups.  This is a tangential 
> issue I guess because by getting smoother backups I'm just going to make 
> their outages shorter, but the outage will still be there.  I'm not 
> backing up from Europe, no.  So connectivity is not an issue.

Does the service really need to be shutdown?
You might solicit opinion and experience from others on
the list about this specific thing.  Personally I don't
shut things down.  Occasionally a file fails during backup,
but it affects only the individual file, not the backup.
And lots of times the "failure" is not really a failure,
more a change between generating the list to backup and
actually backing up the file.  Many times those are simply
temporary files that disappeared in the interim.

But there are some "file changed while being backed up".
Those probably would not recover to a consistant state,
but I've not explored further.  You could experiment and
If it doesn't happen too often, perhaps you don't need
to shutdown.

Another possibility is check if your file system supports
"filesystem snapshots".  If so, generate a snapshot (readonly
and takes little space), backup that static image while the
rest of the world continues using the active filesystem.

I'm not sure, but I think on linux only lvm partitions
support snapshots.

> >If you are willing to use tar as as your backup program (many, many
> >amanda sites do that) then there is not problem.  You say you have
> >basically 400GB of data.  ...
> >... .  So on a typical day, only
> >2 or 3 of the DLEs will get a level 0 and on average your daily
> >backups will be 1/7th of your 400GB or about 60GB/day.
> 
> I have heard of this but I thought that you can only use a directory 
> rather than a partition for a level 0 backup.  If I need daily L1 
> backups, is it still possible with the above scheme?  If it is, then I 
> think thats definitely the way I will go!

You are thinking dump, not tar.

-- 
Jon H. LaBadie                  jon AT jgcomp DOT com
 JG Computing
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