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Rewind Issues with NDMP Attached TAPE DRIVE

Created: 21 Jul 2012 | 9 comments

I would like to know if netbackup does command to rewind a Tape incase of a NDMP attached TAPE DEVICE 

NDMP drive path is configured as nrst0a,nrst1a and so on which is NO-REWIND , but in one of my NDMP logs i found this

My setup has an IBM 03584L32 With  IBM LTO 4ULT3580 ; A windows 64 bit host running NBU 7.1.0.3

what might be the reason for tape rewind ??, any help to resolve this is much appriciated ! 
[kern_ndmpd:info:1573] [ 2322]   INFO: SCSI: TAPE MTIO REWIND 1 nrst0a
[kern_ndmpd:info:1573] [ 2322]  DEBUG: SCSI rewind_unload REWIND
 
0000000f.00306239 00bcd361 Wed Jun 06 2012 15:58:12 -04:00 [kern_ndmpd:info:1573] [ 2322]  DEBUG: SCSI cb_rewind_unload: no problems
0000000f.0030623a 00bcd361 Wed Jun 06 2012 15:58:12 -04:00 [kern_ndmpd:info:1573] [ 2322]  DEBUG: SCSI cb_tape_mtio_rewind_unload: errnum 0: Success or No Error
0000000f.0030623b 00bcd361 Wed Jun 06 2012 15:58:12 -04:00 [kern_ndmpd:info:1573] [ 2322]  DEBUG: cb_ndmp4_tape_mtio: here
0000000f.0030623c 00bcd361 Wed Jun 06 2012 15:58:12 -04:00 
 
[kern_ndmpd:info:1573] [ 2336]  DEBUG: SCSI cb_rewind_unload_steady: called
0000000f.0030d5a0 00bcdcfa Wed Jun 06 2012 16:02:17 -04:00 [kern_ndmpd:info:1573] [ 2336]  DEBUG: SCSI cb_tape_mtio_rewind_unload: errnum 5: NDMPD unix error: Input/output error
 
 
 

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mph999's picture

Netbackup will request tape positioning, it will maove a tape back and forwards at times this is perfectly normal.

BUT ...

NBU does not actually position the tape, it asks either the operating system of the media server, or, the filer to do this positioning, depending on which device the tapes are attached to.

Here it looks lke the tape is going to be rewound so it can be ejected from the drive, but this fails with anIO error.

THis IO error is caused because of a problem between the operating system and the tape drive, nothing to do with NetBackup, or to more accurete very very very unlikely to be netbackup.  THere are a few cases with there has been a bug, or some incompabability with the tape drivers or something, but this is so rare, that I wouldn't consider it until the problem has been investigated starting at the hardware/ operating system.

I/O errors are almost certainly os/ hardware.

In the vast majority of these cases, if you try and investigate / blame NBU, you will never fix it.

One thing that is worth considering is removing and econfiguring the drives from the os level (an therefore NBU) - sometimes this leads to fix.

Martin

Regards,  Martin
 
Setting Logs in NetBackup:
http://www.symantec.com/docs/TECH75805
 
mph999's picture

OK, looking at this again, nrst.. are device files for drives on the filer, so yur drives arae directly connected to the ndmp device.

Looking at a previous case that has this exact error.

Errors will be seen in robots, bptm and ndmp logs.

What is happening, is bptm is sending a scsi commaand via ndmp to the filer to get the tape unloaded, and for some reason, the filer is unable to carry this out.

This is why the messages appear in NBU, NOT because NBU is causing the problem.

The cause of the problem in the case I am looking in is some issue between the filer and the tape drive, which is being investigated by the filer vendor.

Martin

Regards,  Martin
 
Setting Logs in NetBackup:
http://www.symantec.com/docs/TECH75805
 
Subhashathri's picture

Thank you Martin for your inputs 

I have another question

Is there any way you can configure the NBU to force an offline(rew/unload) of the drive as part of the backup sequence even if the tape drive is set to stand alone mode ?

Regards,

mph999's picture

Not on a TLD library no.

The norewind device is confusing you I think.

If you did NOT use a norewind device, as soon as the tape is fast forward to poisition, it would rewind, so, a norewind device is essential, but has no effect on the problem you have.

Forget trying to work around this, that is not the correct solution.

What you need to do is start troubleshooting this at the filer end, and see how you get on.

Although NBU makes requests (eg position tape/ rewind tape) it is the filer that is controlling the tape drive.

Hope this helps.

Martin

Regards,  Martin
 
Setting Logs in NetBackup:
http://www.symantec.com/docs/TECH75805
 
Marianne's picture

Is your ndmp drive indeed configured as standalone?

... even if the tape drive is set to stand alone mode ?

Drive and media usage in robotic library is quite different to standalone.
Important that we understand your configuration.....

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links

mph999's picture

Hi Marianne,

I think the drive is in a library ;

"My setup has an IBM 03584L32 With  IBM LTO 4ULT3580 ; A windows 64 bit host running NBU 7.1.0.3

what might be the reason for tape rewind ??, any help to resolve this is much appriciated ! "
 
However, this is a bit confusing : "... even if the tape drive is set to stand alone mode ?"
 
 
 
I read this as "if the drive is changed to be standalone ... " but as you point out, need to confirm.
M
 
Regards,  Martin
 
Setting Logs in NetBackup:
http://www.symantec.com/docs/TECH75805
 
Subhashathri's picture

Yes , Understanding the setup is more important 

But i would like to reproduce these set of errors in my lab so was just wondering how can i accomplish this to troubleshoot what might be the difference between the one working and one which is not  

Customer has this problem with the below setup 

NBU : 7.0.1.3 ONTAP: 8.1 and IBM 3592 Tape Drive in a library :

Lab Setup:

NBU :7.0.1.3 ONTAP: 8.1 and IBM 3592 Tape Drive configured Standalone mode 

So having the tape drive in stand alone mode and in the library is the difference here 

What I found is having the tape drive configured in stand alone mode does not cause this error. 

Marianne's picture

There is understandably more differences than just standalone and robotic tape drive - HBA in NAS, firmware version, driver version, etc....

Robotic tape drives works fine everywhere else.

You will need to troubleshoot at OS level on the NAS where the problem is seen.

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links

mph999's picture

You can't really troubleshoot an issue if the environments do not match.

I believe, that at Ontap 8.1 there is bug affecting unloading tapes - couold be connected.

Martin

Regards,  Martin
 
Setting Logs in NetBackup:
http://www.symantec.com/docs/TECH75805