Paul,
In the netbackup world I've seen this problem before
and it was caused by the st.conf file.  
--- Paul messner <paul_messner AT STARKEY DOT COM> wrote:

> I should add that this is a new configuration for
> us.
> 
> We add the LTO2 drives to the SAN and enabled DWWN
> on the L700e. We are 
> zoning wwn to wwn.
> 
> We do have some of the tape drive "direct" connected
> to our current backup 
> server with no issues.  But the ones attached to the
> new backup server 
> through the SAN are giving issues.  The errors I am
> seeing in Legato 
> are "cannot decode block, tape positioning disable",
> get an I/O error when 
> labeling a tape (the tape is successful in
> labeling).
> 
> Here are some of the error messages we are seeing.
> 
> Nov  2 13:41:46 thor root: [ID 702911 daemon.notice]
> NetWorker media: 
> (warning) /dev/rmt/S8cbn reading: I/O error
> Nov  2 13:41:46 thor root: [ID 702911 daemon.notice]
> NetWorker media: 
> (warning) /dev/rmt/S8cbn reading: Tape label read
> for volume ? in pool ?, 
> is not recognised by Networker: I/O error
> Nov  2 13:41:48 thor root: [ID 702911 daemon.notice]
> NetWorker media: 
> (info) LTO Ultrium-2 tape  will be over-written
> Nov  2 14:05:09 thor scsi: [ID 107833 kern.warning] 
> WARNING:
>
/pci@1e,600000/pci@0/pci@8/SUNW,qlc@0/fp@0,0/st@w500104f0005daf0a,0
>  (st3):
> Nov  2 14:05:09 thor  Error for Command: write      
>             Error 
> Level: Fatal
> Nov  2 14:05:09 thor scsi: [ID 107833 kern.notice] 
> Requested Block: 
> 761                       Error Block: 761
> Nov  2 14:05:09 thor scsi: [ID 107833 kern.notice] 
> Vendor: 
> IBM                                Serial Number:   
>          
> Nov  2 14:05:09 thor scsi: [ID 107833 kern.notice] 
> Sense Key: Media 
> Error
> Nov  2 14:05:09 thor scsi: [ID 107833 kern.notice] 
> ASC: 0x9 (track 
> following error), ASCQ: 0x0, FRU: 0x36
> Nov  2 14:05:09 thor root: [ID 702911 daemon.notice]
> NetWorker media: 
> (warning) /dev/rmt/S6cbn writing: Invalid argument,
> at file 83 record 763
> Nov  2 14:05:09 thor root: [ID 702911 daemon.notice]
> NetWorker media: 
> (notice) LTO Ultrium-2 tape 206963 on /dev/rmt/S6cbn
> is full
> Nov  2 14:05:09 thor root: [ID 702911 daemon.notice]
> NetWorker media: 
> (notice) LTO Ultrium-2 tape 206963 used 23 GB of 190
> GB capacity
> Nov  2 14:05:48 thor root: [ID 702911 daemon.notice]
> NetWorker media: 
> (notice) Volume "206963" on device "/dev/rmt/S6cbn":
> Block size is 32768 
> bytes not 65536 bytes. Verify the device
> configuration. Tape positioning by 
> record is disabled.
> 
> I do have cases open with Sun and Legato.
> 
> Thanks,
> Paul
> 
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