Christoph Litauer schrieb:
> Dear bacula users,
> 
> I am running bacula 2.4.2 on a linux box. My backups are written to 
> disk1, a raid that is able to read/write about 80MB/s.
> 
> I just did a 'restore all' to another local connected disk (disk2) 
> (80MB/s read/write). While the restore was running I watched the 
> throughput using iostat. I saw disk1 was reading about 70-80 MB/s but 
> disk2 was just writing with 5-6MB/s.
> It seems as if bacula does not just read the essential data from the 
> backup device, instead it reads nearly all backup data and then writes 
> the data that should be restored?
> 
> My disk device is configured
> 
> #
> # File Storage
> #
> Device {
>    Name = FileStorage
>    Device Type = File
>    Media Type = File
>    Archive Device = /storage
>    LabelMedia = yes;
>    Random Access = Yes;
>    AutomaticMount = yes;
>    RemovableMedia = no;
>    AlwaysOpen = no;
>    Block Positioning = yes;
>    Maximum Volume Size = 10737418240     # 10GB
> }
> 
> I think a restore rate of 5-6MB/s is rather slow and I'm shure bacula 
> could do better. Any configuration mistake?
> 

Ok, I'll try an answer myself: As far as I read the documentation the 
performance gap between reading and writing results from bacula not 
storing the exact position for each file. Instead just the job position 
is stored in the database so that restore jobs have to read the whole 
job data.

As a conclusion: As far as I understand this fact, interleaving 
(concurrent writing of up to 20 clients) causes significant performance 
slowdowns while restoring? And would spooling help? Does spooling 
unscramble the interleaved data?

-- 
Regards
Christoph
________________________________________________________________________
Christoph Litauer                  litauer AT uni-koblenz DOT de
Uni Koblenz, Computing Center,     http://www.uni-koblenz.de/~litauer
Postfach 201602, 56016 Koblenz     Fon: +49 261 287-1311, Fax: -100 1311
PGP-Fingerprint: F39C E314 2650 650D 8092 9514 3A56 FBD8 79E3 27B2


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