Veritas Volume Manager 5.0 Release Notes HP-UX 11i v3 (5992-1952, August 2011)

disabling the PFTO feature. You can use the commands mentioned above to re-enable PFTO,
if necessary. For more information, see pfto(7), vxpfto(1M), vxdisk(1M) man pages.
• Enable DMP time-based LUN retries using the following command:
vxdmpadm settune dmp_lun_retry_timeout=120
This system-wide tunable instructs DMP to retry failed I/O requests on a LUN for the time in seconds
specified. The vxdmpadm manpage has not been updated for this release. A brief description of
the new parameter, dmp_lun_retry_timeout is described as follows:
dmp_lun_retry_timeout
When all paths to a disk fail, there may be certain paths that have a temporary failure and are
likely to be restored soon. If I/Os are not retried for a period of time, the I/Os may be failed to
the application layer even though some paths are experiencing a transient failure. For more robust
handling of such transient errors, the dmp_lun_retry_timeout tunable provides a time-based
retry mechanism at the LUN level. If the tunable is set to a non-zero value, I/Os to a disk with all
failed paths will be retried until the dmp_lun_retry_timeout interval expires or until the I/O
succeeds on one of the paths, whichever happens first.
Use the following command to set and retrieve the tunable:
vxdmpadm gettune dmp_lun_retry_timeout
vxdmpadm settune dmp_lun_retry_timeout=<interval>
Where the value for <interval> is in seconds.
The default value of this tunable is 0, which means that the paths are probed only once. HP
recommends a value of 120 seconds.
You need to set the pftostate and dmp_lun_retry_timeout tunables only once as the values
you set are persistent across reboots.
If these tunables are not set as recommended, certain transient I/O error conditions could result
in interruptions to volume availability.
Known Problems And Workarounds
Following known problems exist for the Veritas Volume Manager 5.0:
• “Installation Issues”
• “Utility Issues”
• “Device Issues”
• “Hot-Relocation Issues”
• “Cluster Functionality Issues”
• “Remote Mirror issues”
• “Snapshot and Snapback Issues”
• “Miscellaneous Issues”
• “Veritas Enterprise Administrator Issues”
• “Veritas Volume Manager Web GUI issues”
• “Veritas Volume Manager Software Limitations”
Installation Issues
• Problem
When you upgrade the CVM bundle from 5.0 on HP-UX 11i v2 to 5.0 on HP-UX 11i v3, the
following error messages are displayed:
20 Veritas Volume Manager 5.0 Release Notes