OK. Here are some more information:

We are using a FAS920 with ONTAP 7.0.0.1P7.

There are 28 disks with 73 GB and 28 disks with 146 GB capacity.
The disks are split up into two aggregates: 26 disks (73 GB) with
double parity are "aggr1" and 26 disks (146 GB) with double parity
are "aggr2". The flex-volumes are created within the aggregates.
The left over disks are spare disks (two for each aggregate).

I´ve dumped a 10 GB flex-volume and measured the system load this
morning. The tape writes up to 25 MB/s and the system load was approx
20%. The disks are nearly idle compared to the maximum of 130 MB/s i´ve
seen on the same volume.

And i am using brand new lto-3 tapes as well. And they have new
labels,too.


I will now open a case at netapp.... Perhaps this is a bug in
ONTAP 7.0.0.1P7....

I've been out of the loop for sometime, spending most of my time on the
other side of netapp filers.
But somewhere in the back of my mind I seem to remember that lto3 uses a
different type of tape compared to lto-2.
If this is true then it could be the source of your problem.

On the otherhand: what makes you believe that the backup performance should
increase when you replace the tape drive ?
If the combination filer/filesystem can only supply 25MB/sec then it won't
make a difference if you replace the drive with an lto4/5/6/7/whatever.

You did not tell us the type of filer, the ontap version, the size of the
volume, the raidsize, the raidtype,
and the number of files/average size of the files being backed up. This
would give a lot of information required to see if the filer is really
performing badly or if the situation is normal.

You should not forget that a tape drive is like a hose pipe, the larger the
diameter the more water can be transported, but it is your task to pump

sufficient water into the hose pipe. ;-)

Bye
Ernie

-----Original Message-----
From: Legato NetWorker discussion [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] 
On
Behalf Of Ronny Egner
Sent: Saturday, November 19, 2005 11:11 AM
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Subject: [Networker] Poor performance backing up netapp filer via FC to
LTO-3


Hi list,

we are backing up our netapp filer by ndmp. The tape drive
is connected via fibre channel. We upgraded the drive from lto-2 to lto-3
recently. However: the backup performance  havent changed since then (approx
25 mb/s). The new lto-3 drive should come up with more than 50 mb/s....

Any help ?

To sign off this list, send email to listserv AT listserv.temple DOT edu and type 
"signoff networker" in the
body of the email. Please write to networker-request AT listserv.temple DOT edu 
if you have any problems
wit this list. You can access the archives at 
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER