HP Serviceguard Metrocluster manual Enabling and disabling maintenance mode, Network Attributes

NOTE:

•System multi-node packages cannot be configured in Continentalclusters recovery groups. Multi-node packages are supported only for Oracle with CFS or CVM environments.

•Starting with Continentalclusters version A.08.00, packages in Continentalclusters can be configured as modular packages.

Startup and Switching Characteristics

Normally, an application (package) can run on only one node at a time in a cluster. However, in Continentalclusters, there are two clusters in which an application—the primary package or the recovery package—could operate on the same data. Both the primary and the recovery package must not be allowed to run at the same time. To prevent this, it is important to ensure that packages are not allowed to start automatically and are not started at inappropriate times.

To keep packages from starting up automatically, when a cluster starts, set the AUTO_RUN

(PKG_SWITCHING_ENABLED used prior to Serviceguard A.11.12 parameter for all primary and recovery packages to NO. Then use the cmmodpkg command with the -e <packagename> option to start up only the primary packages and enable switching. The cmrecovercl command, when run, will start up the recovery packages and enable switching during the cluster recovery operation.

CAUTION: After initial testing is complete, the cmrunpkg and cmmodpkg commands or the equivalent options in Serviceguard Manager should never be used to start a recovery package unless cluster recovery has already taken place.

To prevent packages from being started at the wrong time and in the wrong place, use the following strategies:

•Set the AUTO_RUN (PKG_SWITCHING_ENABLED used prior to Serviceguard A.11.12 parameter for all primary and recovery packages to NO.

•Ensure that recovery package names are well known, and that personnel understand they should never be started with a cmrunpkg or cmmodpkg command unless the cmrecovercl command has been invoked first.

•If a cluster has no packages to run before recovery, then do not allow packages to be run on that cluster with Serviceguard Manager.

Network Attributes

Another important difference between the packages configured in Continentalclusters and the packages configured in a standard Serviceguard cluster is that the same or different subnets can be used for primary cluster and recovery cluster configurations. In addition, the same or different relocatable IP addresses can be used for the primary package and its corresponding recovery package. The client application must be designed properly to connect to the appropriate IP address following a recovery operation. For recovery groups with a rehearsal package configured, ensure that the rehearsal package IP address is different from the recovery package IP address.

Enabling and disabling maintenance mode

Any recovery group in Continentalclusters is moved into maintenance mode using cmrecovercl command with —d option. The —d flag is used to disable recovery of the recovery groups.

For Example:

# cmrecovercl —d recovery_group1

Any recovery group in Continentalclusters is moved out of maintenance mode using cmrecovercl command with —e option. The —e flag is used to enable recovery of the recovery groups.

For Example:

Enabling and disabling maintenance mode 57