I had a similar problem few years ago and it was driving me nuts.
It turned out one of our drives (16 total) was bad and damaged tapes.
Not all but some. Then these tapes would get mounted in other drives
which would go down. Absolutely random drives and random times.
I resolved it by painstakingly noting which tape went to which drive and
when it went down. After removing 12-15 tapes everything went back to
normal.

HTH
--Rajmund

-----Original Message-----
From: veritas-bu-bounces AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Len
Boyle
Sent: Wednesday, July 04, 2007 8:49 PM
To: Broun, Bevan; veritas-bu AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] problem with NDMP backups and drives going
down.

Hello Bevan

Do you have the ndmp logs turned on the netbackup server? You might also
want to turn the debug level up to 50 on the filer, but I suspect that
the problem is on the netbackup side of things. 

Do you see any hardware errors in the os error logs?

Have you tried to attach the lto tape drives to the filer to see if that
fixes the problem?

len

-----Original Message-----
From: veritas-bu-bounces AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Broun,
Bevan
Sent: Wednesday, July 04, 2007 9:55 PM
To: veritas-bu AT mailman.eng.auburn DOT edu
Subject: [Veritas-bu] problem with NDMP backups and drives going down.

Hi All

Getting desperate here.

We have:

Netbackup 5.1MP6 (problem existed on MP2) on a windows 2K host.
We have 2 libraries attached: 

    MSL5026 with SDLT drives ultra scsi 3 attached.
    MSL6030 with LTO3 drives connected via fibre HBAs.

We have netapp 920C running data on tap 7.0.5

We have ndmp backups running over ethernet to the netbackup server
(which
gets configured as a ndmp device as per documentation).

Under NB5.1 we need dedicated drives to ndmp and a storage unit created.

All this was/is working perfectly well when we only had the SDLT
library.
NDMP backups ran fine. We brought the MLS6030 because of the capacity
issues.

We configured the MSL6030 drives and ndmp as per what we had prevoiusly
done. Backups run but the drives continually go to down state. Sometimes
it
last a few days, sometimes its a few minutes. Our work around at the
moment
is to up the drives and reboot the netbackup server.

The ndmp 

We have a case raised with symantec but are not getting far. We have
just
raised a case with netapp so they can help. What's the bet that this
forum
get us fixed first :-)

We have upgraded to MP6.
Ugraded firmware on the drives.
Using latest symantec drivers for the library and drives.
Tried using scsi cables rather than via SAN. (this seemed to make it
worse)
library and drive diagnostics from HP show no prolems (hp tape tools
running on the netbackup server).


P:\>set_ndmp_attr -verify gisvof-diamond0-e5b.gi.adi-limited.com
Connecting to host "gisvof-diamond0-e5b.gi.adi-limited.com" as user
"root"...
Waiting for connect notification message...
Opening session--attempting with NDMP protocol version 4...
Opening session--successful with NDMP protocol version 4
host supports MD5 authentication
Getting MD5 challenge from host...
Logging in using MD5 method...
Host info is:
host name "gisvof-diamond0"
os type "NetApp"
os version "NetApp Release 7.0.5"
host id "0101166033"
Login was successful
Host supports LOCAL backup/restore
Host supports 3-way backup/restore


All ideas welcomed.

Thanks all.

Bevan Broun
Systems Engineer
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