Fibre Channel Interface Controller Implementation Issues

KGPSA HBA Error Recovery Settings
6 Fibre Channel Interface Controller Implementation Issues Application Notes
KGPSA HBA Error Recovery Settings
The ResetTPRLO (Third Party Process Logout) driver parameter for cpqkgpsa.sys Fibre
channel driver versions 4.82 and later, is set to a default value of 1. For Enterprise Backup
Solutions (EBS) configurations, HP recommends changing the ResetTPRLO parameter setting
to 2.
With a setting of 0, if the HBA experiences a command time-out due to a transmission error or
similar problem, the driver will send the FC Interface Controller a Target Reset instead of a
TPRLO. The Target Reset will cause the FC Interface Controller to abort all outstanding I/O
commands, clear device reservations, and cause the jobs in progress to fail. Changing the
ResetTPRLO parameter to 2 from the default value of 1, will cause the HBA to precede the
TPRLO command with an ABTS (Abort Sequence). The ABTS will abort all outstanding I/O
operations prior to issuing the TPRLO.
Most backup applications that support Fibre Channel shared device configurations contain
error recovery logic that handles bit error conditions and allows the job in progress to recover
and run to successful completion. In most cases, the Target Reset command circumvents this
logic and causes all active jobs to fail. (Some applications, such as VERITAS NetBackup, have
the ability to recover from this condition.) To correct this situation, the ResetTPRLO
parameter needs to be modified from the default setting of 0 to a setting of 1.
The lputilnt.exe utility for modifying default driver parameters is provided with the
cpqkgpsa.sys driver. As part of the driver installation, this utility is copied to the
C:\WINNT\System32 directory. To modify the ResetTPRLO parameter:
1. Navigate to the C:\WINNT\System32 directory.
2. Start the utility by double-clicking the lputilnt.exe file.
3. In the drop-down box within the utility, select Driver Parameters.
4. Scroll through the list of available parameters to locate ResetTPRLO.
5. Double-click the ResetTPRLO parameter and enter a new value of 2.
6. Select the check box to make the change Permanent and Global and click Save.
The new parameter setting is effective immediately. A reboot of the server is not required.
Note: For configurations that include HP StorageWorks disk array XP or HP StorageWorks VA 74xx
and 71xx disk arrays, disk and tape cannot share the same HBA due to mutually exclusive HBA
driver parameters (KGPSA-BC, KGPSA-CB and FCA-2101 HBAs).
Host/Device Zoning Best Practices
HP recommends using host or initiator-based hard zoning. With hard-zoning, when changes to
the fabric are made, only the affected ports are notified of the changes. By hiding the changes
from unaffected ports, the unaffected ports are not forced to re-establish links with their target
devices.
If soft zoning is necessary, be aware that any changes to the fabric may result in tape drive
errors, failed backup jobs, or retries of current tape operations, which will extend the time
needed to complete the backups.