Asset ID:	1-72-1017291.1
Update Date:	2011-04-14
Keywords:

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Solution Type  Problem Resolution Sure

Solution  1017291.1 :   HP LTO3 - Drive Operates at Reduced Transfer Rate When Daisy Chained to SL500  


PreviouslyPublishedAs
228262

Applies to:

Sun StorageTek SL500 Modular Library System - Version: Not Applicable and later    [Release: N/A and later]
HP LTO3 Tape Drive - Version: Not Applicable and later    [Release: N/A and later]
All Platforms
Checked for relevance on 9-Dec-2010.

Symptoms

Slow performance
B/47/03
0B/47/03
Backup runs slow
Slow transfer rate

Changes

{CHANGE}

Cause

With HP LTO3 drives daisy chained to a L500(SL500) library, the drives will negotiate to a lower transfer rate during write/read operation. In the var/adm/messages file you see "Target 3 reverting to async. mode".
With HP LTO3 drives daisy chained to a L500(SL500) library, the drives will negotiate to a lower transfer rate during write/read operation. In the var/adm/messages file you see "Target 3 reverting to async. mode".

On some occasions, commands are aborted. When this occurs, you will see "Sense Key: Aborted Command" with an ASC 0x47 ASCQ 0x3. OBx4703 is "Information Unit CRC error detected, the drive has detected a CRC error during the command IU or data out phase". This issue has also been seen when there are 3 or more HP LTO 3 drives on the same bus.

Solution

When this issue occurs the typical messages file will look similar to the following:

 

Aug 31 09:02:55 rss57 scsi: [ID 107833 kern.warning] WARNING: /pci@7c0/pci@0/pci@1/pci@0,2/scsi@1 (mpt3):
Aug 31 09:02:55 rss57 Target 3 reverting to async. mode
Aug 31 09:02:55 rss57 mpt: [ID 675377 kern.warning] WARNING: ID[SUNWpd.mpt.sync_wide_backoff.6013]
Aug 31 09:02:55 rss57 scsi: [ID 107833 kern.warning] WARNING: /pci@7c0/pci@0/pci@1/pci@0,2/scsi@1/st@3,0 (st14):
Aug 31 09:02:55 rss57 Error for Command: write Error Level: Fatal
Aug 31 09:02:55 rss57 scsi: [ID 107833 kern.notice] Requested Block: 0 Error Block: 0
Aug 31 09:02:55 rss57 scsi: [ID 107833 kern.notice] Vendor: HP Serial Number: 13:40 rss57 genunix: [ID 936769 kern.notice] px_pci6 is /pci@7c0/pci@0
Aug 30 14:13:40 rss57 px_pci: [ID 37
Aug 31 09:02:55 rss57 scsi: [ID 107833 kern.notice] Sense Key: Aborted Command
Aug 31 09:02:55 rss57 scsi: [ID 107833 kern.notice] ASC: 0x47 (information unit iucrc error detected), ASCQ: 0x3, FRU: 0x013:40 rss57 px_pci: [ID 370704 kern.notice] PCI-device: pci@0,2, px_pci10

 

Corrective Action:

 

At this time, isolate the L500 SCSI controller on its own SCSI bus and do not daisy chain more that two HP LTO 3 drives together.

HP LTO Gen 3, L500, SL500, Daisy chained drives, This is a design issue, audited
Previously Published As STKKB78608

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