[Bacula-bugs] [bacula 0002015]: performance of the Director declines as number of tapes increases

[Mantis B. T. <no...@bu...>]

The following issue has been CONFIRMED. 
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http://bugs.bacula.org/view.php?id=2015 
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Reported By:                paulbong
Assigned To:                
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Project:                    bacula
Issue ID:                   2015
Category:                   Director
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     confirmed
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Date Submitted:             2013-07-17 00:10 BST
Last Modified:              2013-07-17 14:07 BST
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Summary:                    performance of the Director declines as number of
tapes increases
Description: 
# rpm -q -a | grep bacula
bacula-storage-5.2.13-9.fc17.x86_64
bacula-common-5.2.13-9.fc17.x86_64
bacula-libs-sql-5.2.13-9.fc17.x86_64
bacula-client-5.2.13-9.fc17.x86_64
bacula-console-5.2.13-9.fc17.x86_64
bacula-libs-5.2.13-9.fc17.x86_64
bacula-director-5.2.13-9.fc17.x86_64

installed via yum -- did not make from scatch

I use files instead of tapes as the storage devices.  As the number of tape
files increases, the connections to the director get slower and slower.  I
notice the effect start around 20,000 tape files.

Any connection to the director via bconsole and any command that queries the
might show the tape count or next tape are effected (such as 'status' on the
director).

Steps to Reproduce: 
Install bacula and configure to use 'Storage = File' and 'UseVolumeOnce = yes'
then repeatedly backup a small Fileset until you reach 20,000+ files.  Monitor
with trying to connect with bconsole using a command like:
          time echo "status director" | bconsole
(It takes this command "real  1m17.071s" to complete on my machine -- at install
time this command finished in less than a second)

I have seen this happen since early 5.x versions.

I don't know if this manifests itself if you just use a loop to create 20,000+
tape files.



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---------------------------------------------------------------------- 
 (0006728) kern (administrator) - 2013-07-17 14:07
 http://bugs.bacula.org/view.php?id=2015#c6728 
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Bacula was designed to handle a few thousand Volumes (either tape or disk). 
Once you exceed this number you will surely start running into performance
problems.  This performance problem will manifest itself any time Bacula needs
to access the Media table, which is the case of a "status dir" because it is
trying to tell you what the next mounted volume will be.

At some point, these algorithms must be rewritten as users like yourself are
starting to increase their use of Volumes. However, at the moment, there are
other more serious bottlenecks that we are working on, so this one is not at the
top of our list.  I have two suggestions:

1. You implement the algorithm improvements -- we will be happy to work with you
to identify where the problem is an suggest possible ways of resolving it.

2. Bacula was designed to put multiple jobs on a single Volume, so you are
forcing it to work outside its design limits. There is essentially no or very
little performance penalty for putting multiple jobs on a single volume, and in
your case, it could significantly improve performance. Thus the quickest
solution would be to reduce your total number of volumes by 10-100 by putting
more jobs on each Volume.  Using Migration jobs, you can move jobs off of
existing volumes onto a new set that permits having more jobs per volume. 

Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2013-07-17 00:10 paulbong       New Issue                                    
2013-07-17 14:07 kern           Note Added: 0006728                          
2013-07-17 14:07 kern           Status                   new => confirmed    
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