Continentalclusters Version A.07.01 release notes, August 2010 (T2346-90015)

or more nodes in the cluster that is being monitored. In these circumstances, the
cmomd process will continue on the system until terminated by a user. This can
become a significant problem if a monitoring node is powered off and on several
times, leaving several cmomd processes on the monitored cluster, using system
process table space as well as other system resources.
• What is the workaround?
After a failure of the monitoring node, kill the unused cmomd processes.
Provider File Renaming
• What is the problem?
If the provider file, which is named /opt/cmom/providers/cmprovider.omp
by default, is copied to a backup file by adding a prefix to the name (for example,
bk_cmprovider.omp), then Serviceguard will not be able to tell which file is the
correct one.
• What is the workaround?
Do not rename the provider file to a different name by adding a prefix. As an
alternative, store copies or alternate versions of the file in a different directory.
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>
16 Continentalclusters Version A.07.01 Release Notes