Continentalclusters Version A.08.00 Release Notes, April2011 (5900-1485)

Applications hang when all PV links are down
• What is the problem?
When all PV links to a disk array used by a primary or recovery package are down,
the package applications accessing that array will hang indefinitely. The applications
will not detect an error and cannot be killed. Even running cmhaltpkg will not stop
the application.
• What is the workaround?
The default behavior of LVM is to retry access forever following a failure. There are
a number of ways to recover from this application hang problem:
◦ Reboot the node. The package will then move to another node in the cluster.
◦ Fix the problem so that one or more PV Links is restored. The application will
then continue normally.
◦ It is also possible to change the default LVM behavior so that it will not retry
forever. There is an lvchange option that will establish a timeout value which
will cause LVM to return an error to the application if the access to the array has
failed and the timeout period has expired. The command uses the following
format:
lvchange -t <seconds> /dev/<vgname>/<lvname>
This command must be run from one host, on all logical volumes in the package
volume groups. A starting timeout value of 60 seconds is suggested; the timeout
must not be set to less than 60 seconds.
Once the lvchange -t command is run on a host, all other hosts will
automatically inherit the new timeout value for the logical volumes. View the
current timeout value by running thelvdisplaycommand and checking the
value listed for “IO Timeout (Seconds)”. If the value is displayed as “default,”
then LVM will use the default behavior and retry forever.
Continentalclusters does not give proper error message on installation failure
• What is the problem?
When the version of HP-UX Distributed Systems Administration Utilities is less than
C.01.00.11 or the version of HP-UX Secure Shell is less than A.04.50.021, or if
the two products are not installed, the following error message is reported by the
swinstall command during installation of Continentalclusters A.08.00:
Known Problems and Workarounds 21