Hi,

13.10.2009 10:08, justAck wrote:
> Hi,
> I still have to learn bacula internals, but urgently need answer for
> question regarding fragmentation of restored file(s).
> 
> Perhaps someone did backup of heavily fragmented file (size: ~100G) and then
> restored it to clean XFS volume on idle box.
> What is more likely:
> a) result file will be most likely not fragmented on disk at all

This is most likely in the situation you outline.

> b) result file may become fragmented if <some condition>

This is always true - you just need to find the right condition :-)

> c) result file will be as fragmented as initial file was

Very unlikely... Bacula doesn't store information about fragmentation 
of files, so it can't purposely restore in fragments (which would be 
very hard on a normal file system anyway).

> d) result file may be even more fragmented as initial file was

May... sure :-)

> The problem is that copying of restored file is ~20% slower than expected
> (than other files), I doubt if bacula may be a reason of this slowdown (e.g.
> result of restore is very fragmented). 

I doubt that this is caused by file (system) fragmentation. First 
thing to find out is if it's Bacula itself that slows things down, the 
network link between source and target, the target system, or the 
source system.

The most common reasons for slow restores, in my experience, are
- Interleaved data on Baculas volumes. This can happen if you run 
multiple concurrent jobs to the same volume without spooling. Possible 
cure after the fact: Copy or migrate the jobs in question.
- Slow network
- Slow target system. As a first step, use vmstat (on linux) and look 
for high wait time, and use top or ps to find processes using (almost) 
all the CPU.
- Slow source system. Do similar as above, just on the machine running 
the SD.

> Please advice.

Does that help?

Arno


-- 
Arno Lehmann
IT-Service Lehmann
Sandstr. 6, 49080 Osnabrück
www.its-lehmann.de

------------------------------------------------------------------------------
Come build with us! The BlackBerry(R) Developer Conference in SF, CA
is the only developer event you need to attend this year. Jumpstart your
developing skills, take BlackBerry mobile applications to market and stay 
ahead of the curve. Join us from November 9 - 12, 2009. Register now!
http://p.sf.net/sfu/devconference
_______________________________________________
Bacula-users mailing list
Bacula-users AT lists.sourceforge DOT net
https://lists.sourceforge.net/lists/listinfo/bacula-users