Hi, 

> I think you did a really nice investigation work :-) 
Thanks ... was fun :)

> I think that your patch is almost right, and we need to figure if we want to 
> add specific directives for that. I tend to believe right now that with or 
> without the POSIX call, the os will cache the file, and it sounds better to 
> do it in advance, let see what other people are thinking about your idea.

the point is, does it cache the file and evict the cache after the backup of 
the file (what is with posix call) 

Example WITH fix: 
----------------------

  Server: 8 GB unused memory 
  Running Application (aka workload) = 4 of working set and cached files
  Bacula backing up 800 x 100 MB FILE (8 GB in total)

=> After backup

Running Application: 
  If bacula backs up the working set data: 0 GB cached 
  If bacula backs up other sets of data: 4 GB cached (e.g. a Snapshot of the 
dataset which also has new filehandles) <=== Our case !!!!
Bacula 100MB of cached (and never reused) data

OR

does bacula polute the whole file system cache 

Example WITHOUT fix: 
-----------------------------

  Server: 8 GB unused memory 
  Running Application (aka workload) = 4 of working set and cached files
  Bacula backing up 800 x 100 MB FILE (8 GB in total)

=> After backup

Running Application: 0 GB cached 
Bacula 8 GB of cached (and never reused) data


Regards, 
Robert 

Robert Heinzmann
r.heinzmann AT freelancer.traviangames DOT com
IT-Operations
Travian Games GmbH

-----Ursprüngliche Nachricht-----
Von: Eric Bollengier [mailto:eric.bollengier AT baculasystems DOT com] 
Gesendet: Mittwoch, 7. Oktober 2015 16:50
An: Robert Heinzmann <r.heinzmann AT freelancer.traviangames DOT com>
Cc: bacula-users AT lists.sourceforge DOT net <bacula-users AT 
lists.sourceforge DOT net>
Betreff: Re: [Bacula-users] Support for HAVE_POSIX_FADVISE on Bacula Client

Hello Robert,

I think you did a really nice investigation work :-) I think that your patch is 
almost right, and we need to figure if we want to add specific directives for 
that. I tend to believe right now that with or without the POSIX call, the os 
will cache the file, and it sounds better to do it in advance, let see what 
other people are thinking about your idea.

Thanks,
Eric

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