mysterious messages in local.security run output Mail

[hok]

Hello!
My English is bad. I translate with Google. Hopefully they understand me.
For some time I get in the mail the following message. What does this? What's with these snapshots? I'll add more every day - why are only those listed? What are the numbers between the @ @ sign?

Code:

hok-server.local changes in mounted filesystems:
--- /var/log/mount.today	2012-10-25 03:01:01.000000000 +0200
+++ /tmp/security.OtcYcclU	2012-10-26 03:01:00.000000000 +0200
@@ -19,8 +19,6 @@
dp1/Bildarchiv		/mnt/dp1/Bildarchiv	zfs	rw,noatime 	0 0
dp1/CVMA		/mnt/dp1/CVMA		zfs	rw,noatime 	0 0
dp1/Daten		/mnt/dp1/Daten		zfs	rw,noatime 	0 0
-dp1/Daten@auto-20121011.0300-2w /mnt/dp1/Daten/.zfs/snapshot/auto-20121011.0300-2w zfs	ro,noatime 	0 0
-dp1/Daten@auto-20121012.0300-2w /mnt/dp1/Daten/.zfs/snapshot/auto-20121012.0300-2w zfs	ro,noatime 	0 0
dp1/Daten@auto-20121013.0300-2w /mnt/dp1/Daten/.zfs/snapshot/auto-20121013.0300-2w zfs	ro,noatime 	0 0
dp1/Daten@auto-20121014.0300-2w /mnt/dp1/Daten/.zfs/snapshot/auto-20121014.0300-2w zfs	ro,noatime 	0 0
dp1/Daten@auto-20121015.0300-2w /mnt/dp1/Daten/.zfs/snapshot/auto-20121015.0300-2w zfs	ro,noatime 	0 0
@@ -31,6 +29,8 @@
dp1/Daten@auto-20121020.0300-2w /mnt/dp1/Daten/.zfs/snapshot/auto-20121020.0300-2w zfs	ro,noatime 	0 0
dp1/Daten@auto-20121021.0300-2w /mnt/dp1/Daten/.zfs/snapshot/auto-20121021.0300-2w zfs	ro,noatime 	0 0
dp1/Daten@auto-20121022.0300-2w /mnt/dp1/Daten/.zfs/snapshot/auto-20121022.0300-2w zfs	ro,noatime 	0 0
+dp1/Daten@auto-20121023.0300-2w /mnt/dp1/Daten/.zfs/snapshot/auto-20121023.0300-2w zfs	ro,noatime 	0 0
+dp1/Daten@auto-20121025.0300-2w /mnt/dp1/Daten/.zfs/snapshot/auto-20121025.0300-2w zfs	ro,noatime 	0 0
dp2			/mnt/dp2		zfs	rw,noatime 	0 0
dp2/Bahnhof		/mnt/dp2/Bahnhof	zfs	rw,noatime 	0 0
dp2/Media		/mnt/dp2/Media		zfs	rw,noatime 	0 0

The structure of my pools:

Code:

mnt/dp1/Bildarchiv
mnt/dp1/Daten
mnt/dp1/Backup-PC
mnt/dp1/CVMA

mnt/dp2/Media
mnt/dp2/Bahnhof
mnt/dp2/OTR

mnt/Backup/Bildarchiv
mnt/Backup/Daten
...

mnt/Backup2/Media
mnt/Backup2/Daten
...

Of all the datasets are created daily snapshots for 2 weeks.
Where they differ from the others?

Greetings
h.