multiple DLE with tar vs one big DLE with dump (million of files)

Subject:	multiple DLE with tar vs one big DLE with dump (million of files)
From:	FM <dist-list AT LEXUM.UMontreal DOT CA>
To:	Mailing List Amanda User <amanda-users AT amanda DOT org>
Date:	Wed, 01 Oct 2008 10:34:01 -0400

Hello,
We have a lots of performance problems with our Amanda setup.
One of our servers have a 760 GB file system that needs to be backup.
There are 9,286,637 files in this partition. This is the biggest
partition and the most important.

Our holding disk has a size of  886 GB.
We are using Amanda 2.5.0p2
We would have no prob upgrading to 2.6 IF there is a performance boost.

The dumptype for this partition is :

define dumptype tar-high-span-lan {
    program "GNUTAR"
    comment "Partitions dumped with tar"
    compress none
    estimate calcsize
    index yes
    comment "For LAN Servers. High priority partitions dumped with tar
with spanning of 40GB (10% of tape)"
    tape_splitsize 40 Gb
    priority high
}

OR
define dumptype dump-high-lan {
    program "DUMP"
    comment "Partitions dumped with dump"
    estimate calcsize
    index yes
    comment "For LAN Servers. High priority partitions dumped with dump"
    priority high
}
   


Is it better to :
Use dump for the entire partition in one DLE ?
Or split the partition in several partitions and use tar ?