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homerslmpsonFlag for United States of America

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Help with SCSI Tape Drive Issue:

Hi all.
We have 2 external HP LTO2 tape drives that are connected via SCSI connection.
They were chained together and the top one had a terminator on it.  They have separate IDs and worked fine until recently.

Now we recently got an HP LTO4 internal tape drive because we needed more space per tape.
This drive is connected using SAS so it's connecting to a different SCSI card altogether.

The LTO4 tape drive seems to work fine.  We've been using that for the large data but we've been using the LTO2 tape drives (either one) to backup the Exchange database so it clears the log files, etc.

This backup has been failing lately so I decided to use the HP Library and Tape Tools software to see if there is an issue.  

Sure enough, the following is being reported but I'm not sure what it means or how to correct it:
...
The drive is experiencing polling (1.0 / second polling rate) on initiator ID 7.
This could be due to RSM or it could be due to another host.
Polling can interrupt the normal operation of the drive, and significantly reduce performance.
...


FYI - The backup software is CA ARCserve Backup r12.5 SP1 on a Windows Server 2003 machine.
I disconnected one of the 2 LTO2 tape drives just to lessen the chances of a conflict.

Any help would be appreciated.
Avatar of JohnnyCanuck
JohnnyCanuck

SCSI ID 7 is usually the host adapter itself.  It looks like you have 2 host adapters, both with ID 7, in your system.  Try changing the SCSI ID of the adapter  for the LTO2 system to ID 6.
Avatar of Gerald Connolly
But The SCSI ID is per bus and the SCSIHBA and the SAS HBA will show as separate devices.

What else has changed in your hardware config? what happened at the time the backups started failing? is that when the SAS HBA was added or later? Have you replaced the SCSI HBA or either of the LT02 Drives?

Can you post more of the diagnostic output as well?
Avatar of homerslmpson

ASKER

@JohnnyCanuck:
How do you change the SCSI ID of the adapter?  Is it done through software or is there a button somewhere like the external tape drives?

@connollyq:
I can't really answer the questions you're asking.  The 2 LTO2 tape drives stopped working about a week ago.  At first I thought it was one of the tapes.  We are using 2 specific tapes for the Exchange backup on the LTO2 tape drives (either one).  
One tape gets brought off-site and the other gets put in the tape drive for the nights backup.  Then the next day I swap them.  We have one more "spare" Exchange DB tape just in case I wasn't in one day and had the off-site tape with me.  This spare tape has been used a lot less often so I figured that would work but it still failed.

The HP L&TT log files are asking me for a "factory password".  I don't know what they're talking about but there is one other file in the "LOGS" folder that I can read.

It shows that both LTO2 tape drives are experiencing the same type of issue but on different initiator IDs:
"Thu Mar 17 09:00:18 2011 - Alerts for drive SN HU108313EY:

event type: information   event code: 0x411408

Device analysis rule 20:
The drive is experiencing polling (1.0 / second polling rate) on initiator ID 7.
This could be due to RSM or it could be due to another host.
Polling can interrupt the normal operation of the drive, and significantly reduce performance."


Tue Mar 15 13:04:24 2011 - Alerts for drive SN HU19376UWK:

event type: information   event code: 0x411408

Device analysis rule 20:
The drive is experiencing polling (0.8 / second polling rate) on initiator ID 0.
This could be due to RSM or it could be due to another host.
Polling can interrupt the normal operation of the drive, and significantly reduce performance.


I don't know if this helps narrow anything down.

Please keep in mind the following:
- The workstation is a Dell Precision T3400
- The 2 LTO2 tape drives we've had for years
- We ordered and installed a Dell LTO4 internal tape drive but it kept failing so we exchanged it under warranty - they didn't have another Dell so they gave us an HP internal LTO4 drive

Perhaps this is where the problem is?  The LTO4 tape drive that was connected to the SAS HBA has been removed but maybe remnants remain?
"They were chained together and the top one had a terminator on it"

"HAD" does that mean it doesnt anymore?
@connollyq:
There is currently only one LTO2 tape drive connected to the server and it DOES have a terminator.
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homerslmpson
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