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Special Forums Hardware Filesystems, Disks and Memory semaphores and shared memory Post 22688 by Perderabo on Saturday 8th of June 2002 01:50:06 PM
Old 06-08-2002
These are two types IPC facilities. IPC (Inter Process Communication) allows two or more processes to talk with one another. They both require space in kernel tables if they are to be successfully allocated. That's where the SysAdmin comes in. He or she must ensure that there is room for all the IPC's that the system needs.

One example is a relational database management system such as Oracle or Sybase. A RDBMS might have one server program that actually talks to the disk drives. And it would have multiple client programs that need to use the database. The programs communicate via IPC's. And when you install Oracle or Sybase, one of the steps is to review the kernel IPC parameters. They usually will need to be increased.
 

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OCF_HEARTBEAT_ORACLE(7) 					OCF resource agents					   OCF_HEARTBEAT_ORACLE(7)

NAME
ocf_heartbeat_oracle - Manages an Oracle Database instance SYNOPSIS
oracle [start | stop | status | monitor | meta-data | validate-all] DESCRIPTION
Resource script for oracle. Manages an Oracle Database instance as an HA resource. SUPPORTED PARAMETERS
sid The Oracle SID (aka ORACLE_SID). (unique, required, string, no default) home The Oracle home directory (aka ORACLE_HOME). If not specified, then the SID along with its home should be listed in /etc/oratab. (optional, string, no default) user The Oracle owner (aka ORACLE_OWNER). If not specified, then it is set to the owner of file $ORACLE_HOME/dbs/*${ORACLE_SID}.ora. If this does not work for you, just set it explicitely. (optional, string, no default) ipcrm Sometimes IPC objects (shared memory segments and semaphores) belonging to an Oracle instance might be left behind which prevents the instance from starting. It is not easy to figure out which shared segments belong to which instance, in particular when more instances are running as same user. .sp What we use here is the "oradebug" feature and its "ipc" trace utility. It is not optimal to parse the debugging information, but I am not aware of any other way to find out about the IPC information. In case the format or wording of the trace report changes, parsing might fail. There are some precautions, however, to prevent stepping on other peoples toes. There is also a dumpinstipc option which will make us print the IPC objects which belong to the instance. Use it to see if we parse the trace file correctly. .sp Three settings are possible: .sp - none: don't mess with IPC and hope for the best (beware: you'll probably be out of luck, sooner or later) - instance: try to figure out the IPC stuff which belongs to the instance and remove only those (default; should be safe) - orauser: remove all IPC belonging to the user which runs the instance (don't use this if you run more than one instance as same user or if other apps running as this user use IPC) .sp The default setting "instance" should be safe to use, but in that case we cannot guarantee that the instance will start. In case IPC objects were already left around, because, for instance, someone mercilessly killing Oracle processes, there is no way any more to find out which IPC objects should be removed. In that case, human intervention is necessary, and probably _all_ instances running as same user will have to be stopped. The third setting, "orauser", guarantees IPC objects removal, but it does that based only on IPC objects ownership, so you should use that only if every instance runs as separate user. .sp Please report any problems. Suggestions/fixes welcome. (optional, string, default instance) clear_backupmode The clear of the backup mode of ORACLE. (optional, boolean, default false) shutdown_method How to stop Oracle is a matter of taste it seems. The default method ("checkpoint/abort") is: .sp alter system checkpoint; shutdown abort; .sp This should be the fastest safe way bring the instance down. If you find "shutdown abort" distasteful, set this attribute to "immediate" in which case we will .sp shutdown immediate; .sp If you still think that there's even better way to shutdown an Oracle instance we are willing to listen. (optional, string, default checkpoint/abort) SUPPORTED ACTIONS
This resource agent supports the following actions (operations): start Starts the resource. Suggested minimum timeout: 120. stop Stops the resource. Suggested minimum timeout: 120. status Performs a status check. Suggested minimum timeout: 5. monitor Performs a detailed status check. Suggested minimum timeout: 30. Suggested interval: 120. validate-all Performs a validation of the resource configuration. Suggested minimum timeout: 5. methods Suggested minimum timeout: 5. meta-data Retrieves resource agent metadata (internal use only). Suggested minimum timeout: 5. EXAMPLE
The following is an example configuration for a oracle resource using the crm(8) shell: primitive p_oracle ocf:heartbeat:oracle params sid=string op monitor depth="0" timeout="30" interval="120" SEE ALSO
http://www.linux-ha.org/wiki/oracle_(resource_agent) AUTHOR
Linux-HA contributors (see the resource agent source for information about individual authors) resource-agents UNKNOWN 03/09/2014 OCF_HEARTBEAT_ORACLE(7)
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