lunes, 19 de abril de 2010

Oracle RAC O2CB Cluster Service

Oracle RAC O2CB Cluster Service

Before we can do anything with OCFS2 like formatting or mounting the file system, we need to first have OCFS2's cluster stack, O2CB, running (which it will be as a result of the configuration process performed above). The stack includes the following services:

  • NM: Node Manager that keep track of all the nodes in the cluster.conf
  • HB: Heart beat service that issues up/down notifications when nodes join or leave the cluster
  • TCP: Handles communication between the nodes
  • DLM: Distributed lock manager that keeps track of all locks, its owners and status
  • CONFIGFS: User space driven configuration file system mounted at /config
  • DLMFS: User space interface to the kernel space DLM

All of the above cluster services have been packaged in the o2cb system service (/etc/init.d/o2cb). Here is a short listing of some of the more useful commands and options for the o2cb system service.

  • /etc/init.d/o2cb status
    Module "configfs": Not loaded
    Filesystem "configfs": Not mounted
    Module "ocfs2_nodemanager": Not loaded
    Module "ocfs2_dlm": Not loaded
    Module "ocfs2_dlmfs": Not loaded
    Filesystem "ocfs2_dlmfs": Not mounted
    Note that with this example, all of the services are not loaded. I did an "unload" right before executing the "status" option. If you were to check the status of the o2cb service immediately after configuring OCFS using ocfs2console utility, they would all be loaded

  • /etc/init.d/o2cb load
    Loading module "configfs": OK
    Mounting configfs filesystem at /config: OK
    Loading module "ocfs2_nodemanager": OK
    Loading module "ocfs2_dlm": OK
    Loading module "ocfs2_dlmfs": OK
    Mounting ocfs2_dlmfs filesystem at /dlm: OK
    Loads all OCFS modules.

  • /etc/init.d/o2cb online ocfs2
    Starting cluster ocfs2: OK
    The above command will online the cluster we created, ocfs2.

  • /etc/init.d/o2cb offline ocfs2
    Unmounting ocfs2_dlmfs filesystem: OK
    Unloading module "ocfs2_dlmfs": OK
    Unmounting configfs filesystem: OK
    Unloading module "configfs": OK
    The above command will offline the cluster we created, ocfs2.

  • /etc/init.d/o2cb unload
    Cleaning heartbeat on ocfs2: OK
    Stopping cluster ocfs2: OK
http://www.debian-administration.org/articles/578

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