rsync breaks hardware snapshots on HP EVA

We have a novell cluster system NW65SP5 and HP SAN hardware EVA4000 System.

I check the system and found, that the snapshot grow up and have no real
relationship with the change of data on the volume.
I disable the antivirus and the backup system - no change in grow up!

Every day at 18:00 we take hardware snapshot of cluster volumes.
If i run a rsync job (i use rsync.nlm from SP5 - no support from Novell!)
the hardware snapshot grow up to 20 GB in the first 5-10 min of rsync.

The grow up is just at the beginning of building the change log for rsync.

The same grow up is on the user home volume (no rsync jobs). The snapshot
is bigger as hole changes of the user !

This is taken from the HP documentation of snapshots:
"A snapshot is a dependent, point-in-time copy of a virtual disk. It is
dependent because data is not actually copied to the snapshot until it is
overwritten on the source.
Demand allocated—The array allocates only enough space to store metadata
and pointers to the source data. As the source is overwritten, the array
allocates more space and copies the original data to the snapshot."

I check the snapshots with a iso-images file of 0,5 gb.
If i make two copys (overrite) the same iso-images to the volume, the
snapshot grow up to 1,0 gb.(2x 0,5gb).
This works fine,like in the documentation.

The problems must be a os background system task on the server - but i
don´t know how to fix this problem.

How have the same problem and have a fix from Novell or HP ?

Any ideas ?